Class 12

Odisha State Board CHSE Odisha Class 12 Biology Solutions Chapter 8 Evolution Textbook Questions and Answers.

CHSE Odisha 12th Class Biology Chapter 8 Question Answer Evolution

Evolution Class 12 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Choose the correct options

Question 1.
Life originated on earth about
(a) 2.5 billion years ago
(b) 3.5 billion years ago
(c) 4.5 billion years ago
(d) 5.5 billion years ago
Answer:
(c) 4.5 billion years ago

Question 2.
Which theory proposes the formation of living beings from non-living things?
(a) Theory of panspermia
(b) Theory of abiogenesis
(c) Theory of biogenesis
(d) Theory of special creation
Answer:
(b) Theory of abiogenesis

Question 3.
Who proposed the chemical evolution of life?
(a) AI Oparin – JBS Haldane
(b) Louis Pasteur – AI Oparin
(c) Francesco Redi – JBS Haldane
(d) Spallanzani – Louis Pasteur
Answer:
(a) AI Oparin – JBS Haldane

Question 4.
Which of the following compounds Miller-Urey used in the experimental synthesis of amino acids?
(a) CH₄ NH₃,CO₂ and H₂O
(b) CH₄,NH₃,H₂ and H₂O
(c) CH₄,CO₂ H₂ and H₂O
(d) CH₂,N₂,H₂ and H₂O
Answer:
(b) CH₄,NH₃,H₂ and H₂O

Question 5.
Hot ocean water containing concentrated of prebiotic organic compounds was known as
(a) colloid
(b) crystalloid
(c) gelatinous mixture
(d) primordial soup
Answer:
(d) primordial soup

Question 6.
Which of the following was formed first?
(a) Virus
(b) Prokaryote
(c) Coacervates
(d) Eukaryote .
Answer:
(c) Coacervates

Question 7.
A paper on ‘natural selection’ and ‘origin of species’ was presented in the Linnaean Society of London in 1858 by
(a) Charles Darwin – Robert Malthus
(b) Charles Darwin – Alfred R Wallace
(c) Hugo de Vries – Robert Malthus
(d) Alfred R Wallace – August Weismann
Answer:
(b) Charles Darwin-Alfred R Wallace

Question 8.
Analogous organs have
(a) different origin and similar function
(b) similar origin and similar function
(c) similar origin and different function
(d) different origin and different- function
Answer:
(a) different origin and similar function

Question 9.
Find out the odd match.
(a) Aerial-Flying
(b) Fussorial-Burrowing
(c) Cursorial-Running
(d) Arboreal-Swimming
Answer:
(d) Arboreal-swimming

Question 10.
Which one of the following sets of organs constitutes vestigial organs?
(a) Appendix, coccyx and plica semilunaris
(b) Appendix, pectoral girdle and caecum
(c) Large intestine, coccyx and ear muscle
(d) Appendix, coccyx and rectum
Answer:
(a) Appendix, coccyx and plica semilunaris

Question 11.
What is the correct ascending order?
(a) Mesozoic, Cenozoic and Palaeozoic
(b) Cenozoic, Mesozoic and Palaeozoic
(c) Palaeozoic, Mesozoic and Cenozoic
(d) Palaeozoic, Cenozoic and Mesozoic
Answer:
(d) Palaeozoic, Cenozoic and Mesozoic

Question 12.
Who is known as the ’Father of Modern Palaeontology’?
(a) Leonardo da Vinci
(b) Karl Ernst von Baer
(c) Ernst Haeckel
(d) Georges Cuvier
Answer:
(d) Georges Cuvier

Question 13.
Find the incorrect match.
(a) Blood group ‘A’-Antigen A
(b) Blood group ‘AB’-No antibody
(c) Blood group ‘O’-Andgen A and B
(d) Blood group ‘B’-Antibody anti-A
Answer:
(c) Blood group-‘0’-antigen A and B

Question 14.
Which is not a case of chromosomal aberration?
(a) Recombination
(b) Duplication
(c) Inversion
(d) Translocation
Answer:
(a) Recombination

Question 15.
Which type of natural selection removes individuals from both ends of a phenotypic distribution?
(a) Directional
(b) Disruptive
(c) Stabilising
(d) None of these
Answer:
(c) Stabilising

Question 16.
Which is not a great ape?
(a) Gorilla
(b) Chimpanzee
(c) Orangutan
(d) Macaque
Answer:
(d) Macaque

Question 17.
What is the correct sequence in human evolution?
(a) Homo habilis, H. erectus, H. neanderthalensis, H. sapiens
(b) Homo erectus, H. habilis, H. neanderthalensis, H. sapiens
(c) Homo habilis, H. neanderthalensis, H. sapiens, H. erectus
(d) Homo erectus, H. neanderthalensis, H. habilis, H. sapiens
Answer:
(a) Homo habilis, H. erectus, H. neanderthalensis, H. sapiens

Fill in the blanks

Question 1.
Organic evolution refers to a change in diversity and ……….. in populations of organisms.
Answer:
adaptations

Question 2.
The concept of chemical evolution was proposed by JBS Haldane and a Russian scientist, ………… .
Ans
AI Oparin

Question 3.
Charles Robert Darwin hailed from …………….
Ans
Britain

Question 4.
Charles Robert Darwin went on a voyage on board the ship
Answer:
HMS Beagle

Question 5.
Jean Baptiste de Lamarck wrote a book, entitled ……….., which embodied his theory of inheritance of acquired characters.
Answer:
Philosophic Zoologique

Question 6.
Charles Darwin was inspired by the population theory proposed by …………… .
Answer:
Robert Malthus

Question 7.
Darwin’s contemporary ………… was studying population diversity in the erstwhile East Indies.
Answer:
Alfred Russel Wallace

Question 8.
The mutation theory was proposed by ………….. .
Answer:
Hugo de Vries

Question 9.
All the present day life has originated from a single ancestral form, designated as …………. .
Answer:
protobionts

Question 10.
A gene mutation involving only one nucleotide is called as …………….
Answer:
point mutation

Question 11.
Abiogenesis of simple organic molecules was experimentally proved by ………….. and …………..
Answer:
Miller, Urey

Question 12.
The ‘theory of inheritance of acquired characters was proposed by …………. who hailed from …………. .
Answer:
Lamarck, France

Question 13.
August Weismann’s ……….. theory gave a thunder blow to Lamarckism.
Answer:
germplasm

Question 14.
Charles Darwin studied the diversity of a class of birds, commonly known as ………….. in the Galapagos archipelago.
Answer:
Darwin’s finches

Question 15.
The original title of Darwin’s book was ……………. .
Answer:
‘On the origin of species by means of natural selection’.

Question 16.
Natural selection in action was demonstrated by …………. moth.
Answer:
peppered

Question 17.
The earliest form of horse was ………….. that was living in the plains of North America.
Answer:
Eohippus

Question 18.
The fossil of ……….. discovered from the sedimentary rocks of Bavaria, Germany is the missing link between reptiles and birds.
Answer:
Archaeopteryx

Question 19.
Digits II and IV persist in modern horse as reduced structures, known as ……….. bones.
Answer:
splint

Question 20.
Modifications of the basic pentadactyl limb plan in vertebrates to meet their needs is known as ……….
Answer:
homology

Question 21.
The arrangement of different eras, periods and epochs in their ascending order of time constitutes the …………..
Answer:
geological time scale

Question 22.
Peripatus is connecting link between …………. and …………….
Answer:
Annelida, Arthropoda

Question 23.
………… era is known as the era of reptiles.
Answer:
Mesozoic

Question 24.
Sudden reappearance of some ancestral characters in the present organisms is called as ……………
Answer:
atavism

Question 25.
The effect of …………. is larger in small populations and smaller in large populations.
Answer:
genetic drift

Answer each of the following in one word or more words, wherever necessary

Question 1.
The theory that explains that life originated on this planet from non-living chemical constituents.
Answer:
Theory of abiogenesis

Question 2.
The ocean water that contained concentrated amount of prebiotic organic compounds.
Answer:
Primordial soup or prebiotic

Question 3.
The droplets formed by the separation of high molecular weight organic compounds in a colloidal solution.
Answer:
Coacervates

Question 4.
Protenoids, when dissolved in water by boiling and then cooling, organised structures are formed.
Answer:
Microspheres

Question 5.
Buffon, Erasmus Darwin and Lamarck proposed theories on organic evolution, which had one thing in common.
Answer:
Inheritance of acquired characters

Question 6.
Name the naturalist, who proposed that ontogeny recapitulates phylogeny.
Answer:
Ernst Haeckel

Question 7.
Name the theory, which explains about the origin of amphibians from aquatic fish-like ancestors.
Answer:
Recapitulation theory

Question 8.
DNA → RNA → Protein concept.
Answer:
Central dogma

Question 9.
Genetic recombination occurs in cell division. Name the cell division.
Answer:
Meiosis

Question 10.
Hugo de Vries proposed mutation theory on his observations on the morphological features of a plant. Name the plant.
Answer:
Evening primrose (Oenothera lamarckiana)

Question 11.
Breakage, exchange and rejoining of homologous chromosomal segments.
Answer:
Genetic recombination

Question 12.
A single nucleotide substitution in the nucleotide sequence of a gene.
Answer:
Point mutation

Question 13.
The collection of all genes of a population of species.
Answer:
Gene pool

Question 14.
A sudden change in the genetic make up that ends up in a new expression.
Answer:
Mutation

Write whether the following statements are ‘True’or ‘False’

Question 1.
The primitive atmosphere was reducing.
Answer:
True

Question 2.
Heterotrophic organisms with aerobic respiration evolved prior to anaerobic ’ organisms.
Answer:
False

Question 3.
Continuous genetic variation originates through mutation.
Answer:
False

Question 4.
Serum proteins of closely related animals are similar in their amino acid sequences to a greater extent.
Answer:
True

Question 5.
Reptiles flourished in the Palaeozoic era.
Answer:
False

Question 6.
Close similarity in the nucleotide sequence between two organisms depicts close relationship between them. ‘
Answer:
True

Question 7.
Numerical changes, involving one or both chromosomes of a homologous pair, are known as euploidy.
Answer:
True

Question 8.
Genetic drift is the main driving force of evolution in a large randomly breeding population.
Answer:
True

Question 9.
Discontinuous variation is the product of mutation.
Answer:
True

Short Answer Type Questions

Question 1.
Explain the theory of spontaneous generation.
Answer:
Theory of spontaneous generation It states that life originated from non-living matter automatically. This theory is also known as theory of abiogenesis or autobiogenesis. It was also supported by von Helmont (1642), who claimed that the mice were formed in 21 days from a dirty, sweat-soaked shirt put in a wheat barn in the dark. Abiogenesis was continued to be believed till the 17th century.

Question 2.
What do you mean by chemical evolution?
Answer:
This theory was given by AI Oparin (1923) and JBS Haldane (1928). According to them, the first form of life came from pre-existing, non-living organic molecules (like RNA, protein, etc.) and chemical evolution was followed by the formation of life, i.e. formation of diverse organic molecules from inorganic constituents.

The conditions on the earth favouring chemical evolution were high temperature, volcanic storms and reducing atmosphere containing CH₄, NH₃, etc.

Question 3.
Describe Miller-Urey experiment.
Answer:
Stanley Miller and Harold Urey in 1953 performed an experiment to demonstrate that ultraviolet radiations or electrical discharges or a combination of these can produce complex organic compounds from a mixture of CH₄, NH₃, H₂ and water vapour (H20) at 800° C.

Electric discharge was created in a closed glass flask containing CH₄, NH₃, H₂ in the ratio of 2 : 1 : 2 as shown in figure. The conditions were set similar to those of the primitive atmosphere in the laboratory.

They observed the formation of amino acids while in similar experiments performed by other scientists the presence of complex molecules like sugar, pigments, nitrogen bases and fats in the flask were also observed. Further reactions occurred in the aqueous medium of flask resulted in the formation of complex organic molecules at the bottom of flask, such as polysaccharides, fats, proteins, nucleotides and later nucleic acids (DNA and RNA).

Hence, it was concluded that during the beginning of life on earth; complex organic compounds could have formed simpler inorganic precursors.

Question 4.
Explain prebiotic or primordial soup.
Answer:
Formation of molecular aggregates and cell-like structures Aggregates of complex organic molecules were formed in the oceans of the early earth which was termed the ‘Hot dilute soup or prebiotic or primordial soup’ by JBS Haldane (1920). These were considered as precursors of colloidal particles which could grow and divide. These are small complex molecules which are spherical and are covered by external mambranes.

Question 5.
What is prodigality of reproduction ? Give an example.
Answer:
Prodigality of Reproduction (Overproduction):
All organisms possess enormous fertility. They multiply in a geometric proportion with some organisms producing very large number of species. Despite of this high rate of reproduction of a species, its number remains constant under fairly stable environment. The production of more offsprings by some organisms and fewer by others is termed as differential reproduction.

Question 6.
Write three criticisms on Darwinism.
Answer:
Criticism to Darwinism
Darwin’s theory was widely accepted, but Sir Richard Owen and Adam Sedgewick criticised it due to following • reasons
(i) Darwin emphasised on inheritance of useful variations,. However, sometimes inheritance of small variations, which are not useful to individuals are also seen.
(ii) He could not explain the presence of vestigial organs and concept of use and disuse of organs.
(iii) Darwinism failed to explain the arrival of the fittest.
(iv) Darwinism failed to differentiate between the somatic and germinal variations and considered all types of variations as heritable.

Question 7.
Explain how homologous organs reflect organic evolution?
Answer:
Homologous Organs:
It is the relation among the organs of different groups of organisms, that show similarity in the basic structure and embryonic development, but have different functions. Homology in organs indicates common ancestry.
It is based on divergent evolution which leads to the formation of homologous organs.

Question 8.
Describe homology in early embryonic development.
Answer:
Homologous Organs and Homology:
It is the relation among the organs of different groups of organisms, that show similarity in the basic structure and embryonic development, but have different functions. Homology in organs indicates common ancestry.
It is based on divergent evolution which leads to the formation of homologous organs.

In divergent evolution, a same basic organ gets specialisation to perform different functions, in order to adapt to the different environmental conditions prevailing in the habitat, e.g. forelimbs of vertebrates. Examples of homology are as follows

• Structural organisation of vertebrate’s heart, brain, kidney, muscles, skull, etc.
• Different mouthparts of some insects.
• Forelimbs of animals like – whales, bats, cheetah and mammals (e.g. humans).
  

Question 9.
Explain the theory of recapitulation.
Answer:
Recapitulation in embryos Von Baer stated that during the embryo development, distantly related animals depart more and more than do closely animals. Ernst Haeckel (1905) reinterpreted Baer’s law in the form of recapitulation theory in the light of evolution. The theory of recapitulation or biogenetic law states that ontogeny (development of embryo) recapitulates phylogeny (ancestral sequence).

Question 10.
How do fossils support organic evolution?
Answer:
The study of fossil in different sedimentary layers indicates the geological period in which they existed. It also shows that the life forms varied over time and certain life forms are restricted to certain geological time scale. Hence, new forms of life have evolved at different times in the history of earth. All this is called palaeontological evidence.

Question 11.
Why do you call Archaeopteryx as a connecting link between reptiles and birds ?
Answer:
Archaeopteryx is a connecting link between reptiles and birds. It was of the size of crow and had both reptilian and avian characters. Presence of teeth in jaws, fingers having claws, long tail with free caudal vertebrae are the reptilian characters. While, presence of feathers on the body, and forelimbs modified into wings are the avian characters.

Question 12.
What do you mean by a geological time scale?
Answer:
Geological. Time Scale:
It covers the whole span of the earth’s history to correlate the evolutionary events in a proper sequence of ascending order of time. On the basis of time, the geological history of the earth has been divided into five eras namely, Archacozoic, Proterozojc, Palaeozoic, Mesozoic and Coenozoic.

Each era includes several periods and each period is further divided into epochs.
The most primitive era, i.e. Archaeozoic is placed at the bottom and the most recent era, i.e. Cenozoic is placed at the top.

Question 13.
Explain serological test.
Answer:
Serological tests These are tests done to study serum and other bodily fluids in animals. In serological tests, close similarity is found in species of a single genus, while genera of the same family show moderate reaction and families of the same order show slight, but detectable similarity. This indicates that closely related organisms show more similarity in protein structure and function.

Question 14.
What is industrial melanism?
Answer:
Industrial Melanism:
Industrial melanism in peppered moth (Biston betularia) in Manchester city is an example of natural selection. In England, 1850s before industrialisation there were more white-winged moths on trees than dark-winged or melanic forms. But after industrialisation, i.e. in 1920, dark-winged moths became more in number than white-winged moths. This is because during industrialisation, the tree trunks became dark due to air pollution (dust and soot particles).

Question 15.
Explain genetic drift.
Answer:
Random Genetic Drift:
Random genetic drift refers to a random change in gene frequency of a population. In small population, frequencies of particular alleles may change drastically by a single change alone. These changes usually occur randomly.

Sewall Wright recognised this phenomenon as genetic drift (also known as Sewall Wright effect.) In large population, this phenomenon is rare because only favourable variations are selected by nature and unfit variations are eliminated.
Thus, genetic drift acts as the driving force for evolution in large populations.

Question 16.
What is speciation ?
Answer:
Speciation:
It is the process of formation of one or more new species from an existing species due to the accumulation of inversible adaptive change in their structure. A species is a collection of a group of populations with common gene pool (i.e total collection of all genes and its allele in a population). The factors which influence speciation, include mutation, recombination, natural selection, hybridisation, genetic drift, polyploidy (i.e increase in number of chromosomal set) and isolation.

Question 17.
What is bottleneck effect ?
Answer:
Bottleneck Effect:
It occurs when there is a disaster of some sort that reduces the size of a large population to an insignificance. This leaves smaller variation among the small number of surviving individuals, which disables natural selection to operate. In this situation, random genetic drift becomes main driving force of evolution.

Question 18.
What is Hardy-Weinberg’s principle?
Answer:
Mutations introduce new genes into a species resulting in the change in gene frequencies. In 1908, GH Hardy and W Weinberg established a simple mathematical relationship to the study these gene frequencies and gave Hardy-Weinberg principle.

This principle states that the allele frequencies in a . population are stable and is constant from generation to generation, i.e. gene pool remains constant. This is .called genetic equilibrium or Hardy-Weinberg equilibrium.

Differentiate between the following

Question 1.
Abiogenesis and Biogenesis.
Answer:
Differences between abiogenesis and biogenesis are as follows

Abiogenesis	Biogenesis
A theory which describes the origin of life on the earth from non-living thing is called Abiogenesis.	A theory which describes  the origin of life on the earth from pre-existing living organisms is called Biogenesis.
It is based on observations and thoughts.	It was based on practical experiments and ffiaterial evidence.
It was supported by the fungus of bread and production of frogs in the mud.	It was supported by the experiments performed by Redi and Pasteur.
It gives no scientific reasoning about the production of life.	It describes the process of reproduction as an essential ability of living organism.

Question 2.
Chemoautotrophs and Photoautotrophs
Answer:
Differences between chemoautotrophs and photoautotrophs are as follows

Chemoautotrophs	Photoautotrophs
These are the organisms which obtain their energy by oxidising electron donor.	Phototrophs are the organisms that capture protons in order to acquire energy.
Energy source is the oxidizing energy of chemical compounds.	Energy source is mainly sunlight.
Classified as chemoorganotrophs and chemolithotrophs.	Classified as photoautotrophs and photoheterotrophs.
Examples include nitrifying bacteria like Nitrosomonas, sulfur bacteria like Thiothrix, etc.	Some examples are plants algae, cyanobacteria and phytoplanktons.

Question 3. Chemical evolution and Biological evolution.
Answer:
Differences between chemical evolution and biological evolution are as follows

Chemical evolution	Chemical evolution
It occurs due to changes in the structure of molecules from complex molecules to simple molecules with the passage of time.	It occurs due to changes in the structure of molecules from complex molecules to simple molecules with the passage of time.
It is relatively fast process and hence, it is possible to prove it in a laboratory.	It is relatively fast process and hence, it is possible to prove it in a laboratory.
It involves the evolution of chemical such as water vapour, methane, ammonia and hydrogen into organic molecules such as sugars which later combined to form big molecules such as proteins, RNA and DNA.	It involves the evolution of chemical such as water vapour, methane, ammonia and hydrogen into organic molecules such as sugars which later combined to form big molecules such as proteins, RNA and DNA.
Chemical evolution came into act before organic evolution.	Organic evolution is a consequence of biological evolution.

Question 4.
Homologous organs and Analogous organs.
Answer:
Differences between homologous organs and analogous organs

Homologous organs	Analogous organs
They have same basic structural plan.	They have totally different structural plan.
They are found in closely related organisms which arise from some common ancestor.	These organs found in totally unrelated organisms.
They differ in appearance.	They have similar appearance.
They are modified to carry out different functions.	These organs carry out the same function.
They lead to adaptive radiation or divergent evolution.	They lead to convergent evolution or adaptive convergence.

Question 5.
Moulds and Casts.
Answer:
Differences between moulds and casts are as follows

Moulds	Casts
A mold is a cavity left behind when the organic material is dissolved away. Only the external impressions remain during fossilisation.	A cast is usually a very finely preserved representation of the surface features of the organism during fossilisation.

Question 6.
Genetic recombination and Mutation.
Answer:
Differences between genetic recombination and mutation are as follows

Genetic recombination	Mutation
It is the production of offspring with combinations of traits that differ from those found in either parents.	It is random nucleotide alterations such as copying errors or changes induced by external mutagens.
It is performed by the cell during the preparation of gametes (sperm, egg, pollen) which are used for sexual reproduction.	It may take place both in somatic cells and germline cells.
Genetic recombination is heritable.	Mutation can be heritable as well as non-heritable.

Question 7.
Somatic variation and Germinal variation.
Answer:
Differences between somatic variations and germinal variations are as follows

Somatic variations	Germinal variations
Somatic variations are the variations in the somatic cells of an organism which may be acquired by them in their life.	Germinal variations are the variations in the germ cells of an organism.
These are not passed on to their progenies.	These are passed on to their progenies.

Question 8.
Chromosomal aberration and Gene mutation.
Answer:
Differences between chromosomal aberration and gene mutation are as follows

Chromosomal aberration	Gene mutation
Chromosomal aberration is any change in the number and structure of chromosomes in an organism.	Gene mutation is an alteration that occurs in the DNA base sequence of a gene.
It can change the total number of chromosomes in an organism.	Gene mutation does not cause changes in the total number of chromosomes in an organism.
It may include many gene alterations.	Gene mutation commonly refers to a single gene alteration.
Damages due to chromosomal aberration are large scale compared to gene mutation.	Nucleotide damage is small in scale compared to chromosomal aberration. However, it can cause serious health problems.

Question 9.
Euploidy and Aneuploidy.
Answer:
Differences between euploidy and aneuploidy are as follows

Euploidy	Aneuploidy
Euploidy is a variation in a chromosomal set of a cell or organism.	Aneuploidy is a variation in total chromosome number of a cell or organism.
The number of chromosome sets is changed.	The number of chromosome sets is not changed.
Cells have states of 3n, An, etc.	Ceils are in the states of 2n+1, 2n-1, n-1,n+1, etc.
Euploidy occurs due to fertilisation of one ovum with two sperms, etc.	Aneuploidy arises due to non-disjunction in meosis I and II and mitosis.
Euploidy is not seen in humans.	Aneuploidy is seen in humans.

Question 10.
Natural selection and Genetic drift.
Answer:
Differences between natural selection and genetic drift are as follows

Natural selection	Genetic drift
It is a process where more adaptive species are selected in response to the environmental challenges.	It is a random selection.
It occurs due to environmental challenges.	It does not occur due to environmental challenges.
It ends up with selecting the more successive trait over the detrimental trait.	Due to genetic drift important alleles may disappear completely.
It increases the frequency of the trait more adaptive to the environment.	Genetic drift rarely results in more adaptive species to the environment.
It increases genetic variation.	It does not increase genetic variation. Infact, sometimes it causes some variants to be extinct completely.

Question 11.
Convergent evolution and Divergent evolution
Answer:
Differences between convergent evolution and divergent evolution are as follows

Convergent evolution	Divergent evolution
It is supported by the analogous structures.	It is supported by the homologous structures.
It occurs in organisms which are not closely phylogenetically related.	It occurs in phylogenetically related organisms.
Example insects, birds, pterosaus and bats. All have developed the similar nature of the flight/wings.	Example Darwin’s finches.

Long Answer Type Questions

Question 1.
Give an account of the chemical basis of origin of life.
Answer:
Life on earth appeared 500 million years after its formation. In order to explain origin of life on the earth, different theories were given by different thinkers and scientists. They are
1. Theory of special creation It states that God has created life by his divine act of creation, i.e. the earth, light, plants and animals are all being created by the supernatural power.

2. Theory of catastrophism It states the creation of new life forms occurred after each catastrophe on earth.

3. Cosmozoic theory or Theory of panspermia It was given by early Greek thinkers, which states that the life on earth arose from the spores or panspermia, which came from outer space and developed into living forms.
The above three theories have been discarded due to the lack of logical explanation. Later on few more theories were proposed to explain the orgin of life.
These are
(i) Theory of spontaneous generation It states that life originated from non-living matter automatically. This theory is also known as theory of abiogenesis or autobiogenesis. It was also supported by von Helmont (1642), who claimed that the mice were formed in 21 days from a dirty, sweat-soaked shirt put in a wheat barn in the dark. Abiogenesis was continued to be believed till the 17th century.

(ii) Theory of biogenesis According to this theory, life originates from pre-existing life. This theory was supported by some scientists like Francisco Reddi (1668), Lazzaro Spallanzani (1767), Louis Pasteur (1862), Harvey and Huxley.

Chemical Evolution:
This theory was given by AI Oparin (1923) and JBS Haldane (1928). According to them, the first form of life came from pre-existing, non-living organic molecules (like RNA, protein, etc.) and chemical evolution was followed by the formation of life, i.e. formation of diverse organic molecules from inorganic constituents.
The conditions on the earth favouring chemical evolution were high temperature, volcanic storms and reducing atmosphere containing CH₄, NH₃, etc.
Chemical Evolution has Occurred in Following Steps

(i) Primitive earth had no atmosphere and it was anaerobic. Initially, the earth was a ball of hot gaseous mass.

(ii) Formation of Early Molecules
(a) Earth gradually began to cool and condense into a solid form. As a result, the free atoms or elements present on earth began to segregate into three concentric masses according to their weight.

(b) The heavier elements like nickel, iron, etc., moved to the core of the earth, intermediate one like silicon and aluminium moved to the middle and the lighter elements like oxygen, nitrogen, hydrogen, carbon, etc., remained on the surface and formed the early atmosphere of earth.

(c) With further cooling of the earth lighter elements such as water (H₂O), methane (CH₄), ammonia (NH₃), hydrogen cyanide (HCN) . and oxides of carbon were formed. The primary atmosphare was devoid of free molecular oxygen (O₂) due to which it was of reducing type.
Hot oceans, seas, lakes and other water bodies were formed due to the accumulation of heavy rainwater in the depressions of the earth.

(iii) Formation of simple organic molecules The high concentration of simple inorganic compounds (CH₄,HCN,NH₃) in water bodies induces them to react with each other so as to produce some unsaturated hydrocarbons.

As a result of further interaction of these hydrocarbons, some simple organic compounds such as simple sugars (e.g. glucose, ribose, deoxyribose, etc.), nitrogenous bases (purines like adenine, guanine and pyrimidines like thymine, cytosine and uracil), amino acids, fatty acids and glycerols were formed.

The energy required for these reactions came from the following sources

• Solar radiations like ultraviolet light (UV) rays, cosmic rays and X-rays, etc.
• Electrical discharge from lightning. High energy radiations from radioactive unstable isotopes on primitive earth.

(iv) Formation of complex organic molecules A number of hydrocarbons, purines and pyrimidine bases, amino acids, fatty acids, sugars and other organic compounds were accumulated in the primitive seas. Further reactions like polymerisation lead to the formation of larger organic molecules which later on formed complex organic molecules like polysaccharides, fats, proteins, nucleotides and then nucleic acids (DNA and RNA).

(v) Formation of molecular aggregates and cell-like structures Aggregates of complex organic molecules were formed in the oceans of the early earth which was termed the ‘Hot dilute soup or prebiotic or primordial soup’ by JBS Haldane (1920). These were considered as precursors of colloidal particles which could grow and divide. These are small complex molecules which are spherical and are covered by external mambranes.
These colloidal aggregrates were called coacervates by Oparin and microspheres by Sydney Fox (1965).

The firest non-cellular cells were believed to contain nucleoproteins and other macromolecules like polypeptides, lipids, etc. These cells were called protocells or protobionts or eubionts and they in the ancient ocean represented the beginning of life approx. 3.5 billion years ago. Probably viruses were evolved at the same time.

The first cellular life forms are believed to be evolved approximately 2 billion years back by the aggregation of various non-living molecules. From there, the evolution of diverse species of organisms occurred in course of time.

Question 2.
Discuss the evidences of organic evolution from comparative anatomy and morphology.
Answer:
Evidences from Comparative Anatomy and Morphology
These evidences help to identify the similarities and differences among the organisms of today and those that existed years ago. Comparative study of external and internal structure can be used to understand the occurrence of organic evolution.

These can be determined by the following types
Homologous Organs and Homology
It is the relation among the organs of different groups of organisms, that show similarity in the basic structure and
embryonic development, but have different functions. Homology in organs indicates common ancestry.
It is based on divergent evolution which leads to the formation of homologous organs.

In divergent evolution, a same basic organ gets specialisation to perform different functions, in order to ‘ adapt to the different environmental conditions prevailing in the habitat, e.g. forelimbs of vertebrates. Examples of homology are as follows

• Structural organisation of vertebrate’s heart, brain, kidney, muscles, skull, etc.
• Different mouthparts of some insects.
• Forelimbs of animals like – whales, bats, cheetah and mammals (e.g. humans).
  
  Flomologous organs as exhibited by the forelimbs of vertebrates; (a) Fluman, (b) Bat, (c) Whale, (d) Horse

Adaptive Radiation (Divergent Evolution):
It is the diversification of the organisms of a population into a number of new groups with adaptive characters suiting their need for survival.

Thus, it can be concluded that adaptive radiation and divergent evolution are interrelated and based on the modification of homologous structures. This can be proved studying the basic pattern of the pentadactyl limb which has undergone adaptive modifications in vertebrates,

All these animals have five digits (pentadactyl) in their forelimbs. All these digits possess the same number of skeletal elements that are arranged in same order (i.e. proximal to distal) along with similar muscle, nerve fibres, blood vessels, etc. These limbs have undergone adaptive modifications so as to perform the required funtions to adapt to their environment.

Similar adaptive modification rule also applies to mammals. In figure, a typical pentadactyl limb is seen in a terrestrial mammal.

Adaptive radiation in the limb structure of mammals

This pattern has been modified for different functions like running (cursorial), swimming (aquatic), flying (aerial), climbing (arboreal) and burrowing (fussorial). Thus, all mammals have originated from an ancestral terestrial mammal through adaptive modifications of the basic pentadactyl limb plan.

Analogous Organs and Analogy:
In contrast to homologous organs, the analogous organs are different in their basic structure and developmental origin, but appear same and perform similar functions.
This relationship between the structures of different groups of animals due to their similar functions is called analogy or convergent evolution.

Examples of analogy are as follows
1. Wings of an insect a bird, Pterosaur (extinct flying reptile and a bat (flying mammal) show analogy. The wings are modified forelimbs that are adapted for flight.
The internal organisation of vertebrate (reptile, bird and bat) wings is same and they are composed of muscles and bones whereas, the wings of insect do not possess bones and muscles. They are only thin membranous extentions of exoskeleton and are made up of chitin.

2. Flippers of dolphin and penguin.
3. Fins of fishes and flippers of whales.
4. Tracheae of an insect and lungs of the vertebrates are adapted for respiration, but are not homologous, as tracheae are ectodermal in origin, whereas the lungs are endodermal in origin.

Adaptive Convergence (Convergent Evolution):
In adaptive convergence, separate lineages show similar morphology under the influence of similar environmental factors. The existence of analogous structures also suggest the occurrence of convergent evolution. It may be explained in terms of the environment acting through the agency of natural selection and favouring those variations which confer increased survival and reproductive potential of the organisms possessing them.
Marsupial mammals in Australia are a good example to study adaptive convergence or convergent evolution.

Vestigial Organs:
The degenerated, rudimentary organs which are non-functional in the possessor, but were functional in their ancestor and in related animals are called vestigial organs. There are more than 90 vestigial organs in the human body. Some examples in human are coccyx (tailbone), nictitating membrane ( semilunar fold or plica semilunaries or 3rd eyelid), caecum, vermiform appendix, canines, wisdom teeth, tonsils, body hair, auricular muscles, mammary glands in males, etc.

Vestigial organs are present in some other animals also, e.g. splint bones representing metacarpals of digits II and IV in horse, small bones representing hindlimbs and pelvic girdle in python and boas, wings and feathers in flightless bird kiwi of New Zealand, etc.

In plants, Dandelions and some other asexually reproducing plants retains flower which produce pollen grains necessary for sexual reproduction.

Atavism or Reversion:
It is the sudden reappearance or refunctioning of some ancestral organs, which have either completely disappeared or are present as vestigial organs.

It supports the idea of organic evolution, that living organisms have the ability to develop even lost or non-functional structures. For example, long and dense body hair, ability to move pinna in .some individuals, birth of a human baby with a small tail, presence of additional mammae in some individuals, elongated canine teeth, etc.

Question 3.
Give an account of the embryological evidences of organic evolution.
Answer:
Evidences from Embryology:
Similarities and degree of intimacy in the embryonic development of various animals provide the supportive evidences of organic evolution. Some conclusions are derived from the study of comparative embryology, which are as follows

1. Common developmental pattern A common pattern of development is found in all the multicellular organisms. The development of embryo by sexual reproduction starts from diploid zygote or fertilised egg. The zygote undergoes repeated cleavage or cell division to form a solid structure called morula. The morula divides to form blastula, i.e. a single-layered hollow structure, which finally develops into gastrula, i.e. two to three-layered structure.

The animals with two-layered gastrula are termed as diploblastic, e.g. in coelenterates. The animals in which three-layered gastrula is found are known as triploblastic, e.g. frog, lizard, etc. These two or three layers of gastrula are termed as primary germ layers, which give rise to the entire animal. Thus, the similar early embryonic development shows close relationship among all the multicellular organisms.

2. Similarity in early embryos of vertebrates If a comparative study of embryos of vertebrates at same age is done, it is observed that they resemble one another. Such similarities suggest that these animals have common ancestry.

Some similarities in early embryonic stages are as follows
Presence of gill clefts, notochord, tail, rudimentary eyes and ears, etc. in all vertebrates from fishes to mammals.
Notochord is replaced by vertebral column in all adult vertebrates.
Gills are replaced by lungs in adult amphibians, reptiles and mammals.

3.Recapitulation in embryos Von Baer stated that during the embryo development, distantly related animals depart more and more than do closely animals. Ernst Haeckel (1905) reinterpreted Baer’s law in the form of recapitulation theory in the light of evolution. The theory of recapitulation or biogenetic law states that ontogeny (development of embryo) recapitulates phylogeny (ancestral sequence).

This means that the life history of an animal reflects its evolutionary history. For example, during the life history, frog’s tadpole larva resembles fishes in habits and structure. It suggests that amphibians have evolved from fish ancestors.
Embryo logical Evidences in Plants

These include

• Presence of filamentous green algae-like structure, i. e. protonema during development of Funaria (moss).
• Pteridophytes and primitive -gymnosperms like Cycas and Ginkgo have flagellated sperms and they depend on water for fertilisation. It strengthens the fact that gymnosperms have evolved from pteridophytes.

Question 4.
Describe palaeontological evidences of organic evolution.
Answer:
Evidences from Palaeontology:
Palaeontology is the study of fossils of plants and animals that lived in prehistoric times. Leonardo da Vinci (1452-1519), an Italian painter is known as the ‘Father of Palaeontology’ and Baron Georges Cuvier (1769-1832) is known as ‘The Founder of Modern Palaeontology’.

The study of fossil in different sedimentary layers indicates the geological period in which they existed. It also shows that the life forms varied over time and certain life forms are restricted to certain geological time scale. Hence, new forms of life have evolved at different times in the history of earth. All this is called palaeontological evidence.

Fossils:
These are the material remains (bones, teeth, shells) or traces (physical or chemical) of ancient organisms induding plants and animals. According to Charles Lyell, fossil is any body or traces of body of animal or plant buried and preserved by the natural causes. .

Fossilisation is the process of formation of fossils. Fossils are generally preserved in sedimentary rocks in which multiple layers are present and the lowermost layer gets harden into rock under pressure. These are formed when parts of dead organisms decay with the passage of time and get replaced by inorganic materials. The hard parts of the body (i.e. bone, teeth, shell, etc.), are preserved more readily than soft parts, into rocks. Both animals as well as plants can be fossilised as additional layers get deposited with time.

Fossils are also formed by processes other than petrification, e.g. an organism may get buried intact in ‘ preservatives like resins, snow, oil, tar, volcanic, ash, etc.

Sometimes, the organism or its parts get washed away to water bodies and settle down at the bottom. Gradually they get covered by the layers of mud and sand. Particularly when buried in rapidly hardening mud, they decay completely and the space it occupies, becomes filled with another kind of material forming moulds and casts.

Types of Fossils:
Some general types of fossils are given below
(i) Unaltered It includes animals, plants and humans who got embedded in permafrost of arctic/alpine snow and remain preserved in actual state, e.g. wooly mammoth (25000 years old in Siberia) and insects trapped in the amber of plants.
(ii) Petrifications The fossils in which hard body parts (organic matter) get replaced by mineral matter like silica, pyrites and calcium, etc. In some petrified fossils, even cellular details are found. This process is used to preserve original structures of organisms.
(iii) Moulds They are hardened encasements formed in the outer parts of extinct organic remains which later decayed leaving cavities.
(iv) Casts They are hardened pieces of mineral matter deposited in the cavities of moulds.
(v) Impressions/Imprints They are external features of organisms or their parts that are left due to hardening rocky matter before they completely decay.

(a) Imprint of a crustacean, (b) Mould of a bivale, (c) Insect trapped in amber, (d) Petrified softwood, (e) Petrified cone of Araucaria mirabilis (a coniferous tree)

Important Characteristics of Fossils:
The fossil records are direct evidences that support organic evolution due to the following reasons
1. Fossils of different ages are mostly found in the different layers of sedimentary rocks in an ascending order, i.e. from simple to complex forms.

2. The lower layers of rocks of early era contain fossils of simple nature. In upper layers more recent fossils, which are more recent and complex in structure. Fossils are not found in the rocks of the Archaeozoic (first) Era.

3. In the rocks of the second era, i.e. Proterozoic, only few fossils are found. These are simple, soft-bodied organisms, such as marine invertebrates. In the upper strata of rocks, fossils are more in number, belonging to organisms of later ages.

4. The fossils of two consecutive strata are different from each other indicating the occurrence of progressive changes in course of time.

5. Certain mammals, such as horse, elephant, camel and man, have complete fossil records. They clearly explain the gradual evolution of these species.

6. Fossils of some transitional forms (also called connecting links or missing links) explain the emergence of a new species from its ancestor. For example, fossil of Archaeopteryx discovered from the rocks of Jurassic Period at Bavaria, Germany in 1861 is a connecting link between birds and reptiles. As a transitional form, it possessed the characters of both reptiles and birds.

7. Living fossils are the living organisms which are similar in appearance to a recorded fossil of distant ancestors but they usually have no close relatives. Such organisms have undergone very slow changes over a long span of time, e.g Latimeria (a coelacanth fish).

8. The approximate ages of fossils can be determined by different radioactive dating methods.

9. Extinction of species can be explained by the fossil records of that species, e.g. dinosaurs extinct about 66 million years ago.

Question 5.
Describe Darwin’s theory of natural selection and origin of species and discuss about the criticisms.
Answer:
Darwinism (Natural Selection Theory):
Charles Robert Darwin was born in 1809. In 1831, he accepted an unpaid post of naturalist on the survey ship, called HMS Beagle. In his voyage, he spent five years in sea charting the East Coast of South America. During a five week stay on the Galapagos Archipelago Islands, he was struck by the similarities shown by the flora and fauna of the islands and mainland. In particular, he was intrigued by the characteristic distribution of species of tortoises and finches.

Darwin observed different types of beaks in the same population of finches. He termed this phenomenon as adaptive radiation which explains that the changes in beak structure were the result of adaptations to the available food to the native finches. Over the years, the ancestral beak evolved into diverse types of beaks. Thus, Darwin realised the importance of competition and adaptation in the evolution of finches.

After his return, Darwin formulated his concept of organic evolution. He was also influenced by a paper published by Robert Malthus (1838) on populations, which states that the population increases in a geometric progression, while the food supply increases more slowly. Therefore, the food supply becomes a limiting factor. In the meantime, another naturalist Alfred Russel Wallace, came to the same conclusions as Darwin regarding natural selection. The content of Wallace’s write-up was similar to Darwin’s thinking.

Darwin and Wallace presented papers on their ideas which were published in the ‘Journal of the Proceedings of The Linnaean Society of London in 1858. Darwin published a book entitled ‘On the Origin of Species by Means of Natural Selection (later changed to ‘Origin of Species’ In its 6th edition in 1872), embodying his observations and conclusions in 1859.

Postulates of Darwinism:
The main postulates, which formed the basis of Darwin’s theory of natural selection are as follows
(i) Prodigality of Reproduction (Overproduction):
All organisms possess enormous fertility. They multiply in a geometric proportion with some organisms producing very large number of species. Despite of this high rate of reproduction of a species, its number remains constant under fairly stable environment. The production of more offsprings by some organisms and fewer by others is termed as differential reproduction.

(ii) Limiting Factors
The resources like food, space, etc., remain limited inspite of rapid multiplication of the individuals of all the species. It helps to check the increased number of animals and plants.

(iii) Struggle for Existence
The limited amount of resources and overproduction of organisms are the main causes of struggle for existence. Various types of struggle help an organism to cope up with unfavourable environmental conditions.
The three types of struggles are as follows
(a) Intraspecific struggle It is the struggle among the individuals of same species for their common requirements like food, shelter, mate, breeding places, etc.
(b) Interspecific struggle It is the struggle between the individuals of different species for their similar requirements like food and space.
(c) Environmental struggle It is the struggle of living forms against the environmental conditions like extreme heat, cold, drought, earthquakes, storms, disease, volcanic eruption, etc.

(iv) Variations and Heredity
All individuals are dissimilar in some of their characters except the identical twins. This dissimilarities are mainly due to the variations. These are the small or large differences among the individuals. Variations allow some individuals to better adjust with their environment.

Variations can be categorised into the following types
1. Somatic variations These variations affect the somatic cells of an organism. They are also called modifications or acquired characters because they are aquired by an individual during its lifetime. These are caused by various environmental factors, use and disuse of organs and conscious efforts, etc.
2. Germinal variations These are inheritable variations recognised by Darwin but he had no idea of inheritance of characters. They are formed mostly in germinal cells. They are further of two types
• Continuous (gradual) variations These are fluctuating variations, which oscillate due to race, variety and species.
• Discontinuous (sudden) variations These appear suddenly and show no ‘spots’ gradation. These variations were termed as ‘spots’ by Darwin and ‘mutation’ by Hugo de Vries. Darwin regarded continuous variations to be more important because the discontinuous variations being mostly harmful would not be selected again.

(v) Survival of the Fittest and Natural Selection:
The organisms, which have inherited favourable variations generally survive. This is termed as ‘survival of the fittest’ (the phrase being originally used by Herbert Spencer). Whereas, the organisms without such variations appear unfit and get eliminated. Nature plays a decisive role in selecting the fit organisms.

Natural selection is based on merit and is without any prejudice or bias. It eliminates the unfit ones and selects those organisms that are most fit to survive in a particular environment and to produce offsprings. Survival alone does not make any sense from evolution point of view.
The fit organisms must reproduce to contribute to the next generation. Lerner (1959) says, ‘Individuals having more offsprings are the fit ones’.

(vi) Origin of New Species (Speciation):
Darwin considered that as a result of struggle for existence, variability (continuous variations) and inheritance, species became better adapted to their environment. These beneficial adaptations are preserved and accumulated in the individuals of species generation after generation. This results into the origin of new species or speciation and the resultant offsprings become visibly distinct from their ancestors.

Criticism to Darwinism:
Darwin’s theory was widely accepted, but Sir Richard Owen and Adam Sedgewick criticised it due to following reasons
(i) Darwin emphasised on inheritance of useful variations,. However, sometimes inheritance of small variations, which are not useful to individuals are also seen.
(ii) He could not explain the presence of vestigial organs and concept of use and disuse of organs.
(iii) Darwinism failed to explain the arrival of the fittest.
(iv) Darwinism failed to differentiate between the somatic and germinal variations and considered all types of variations as heritable.
(v) Darwin’s natural selection theory was based on the mistaken concept of artificial selection. He wrongly believed that changes brought on by domestication of animal were also heritable.
(vi) Darwin failed to recognise the large fluctuating variations (occurring due to mutation). He only believed in the occurrence of small continuous variations.

Darwin proposed ‘theory of pangenesis’ explaining that pangenes or gemmules are transmitted from one generation to next. However, this theory was refuted by Weismann’s germplasm theory.

Question 6.
Discuss about the synthetic theory of organic evolution.
Answer:
Modern Synthetic Theory of Organic Evolution:
The fundamental mechanisim of evolution as explained by Darwin and his contemporaries underwent major modification with the progress in genetics.

Mendel’s laws of inheritance were applied to various theories (like natural selection). The validity of these laws were later verified by Correns, Tschermark and de Vries. It came to light that mutation and genetic recombination were the cause of genetic variation in living organisms.

These variations were used as the raw material on which natural selection acted on, leading to evolution of new species. The process of evolution as a population character not an individual one was later on proposed by GH Hardy and W Weinberg. According to them, a disturbance in the gene pool of a population results in evolution. Among these new developments, the concept of modern synthetic theory (post-Darwinian synthesis) was proposed.

The modern synthetic theory is based on the work of a number of scientist namely-Dobzhansky’s (1937) Julian Huxley (1942), Ernst Mayr (1970), RA Fisher (1958), JBS Haldane, Sewall Wright (1968) and GL Stebbins (1971). Stebbins in his book ‘Process of Organic Evolution discussed the modern synthetic theory.

This theory is a collective explanation of the fundamental mechanism of evolution. Homologous recombination, mutation, natural selection, isolation, genetic drift and migration form the basis of the mechanism of evolution.

Genetic Recombination:
These are the homologous combinations between genes present on different chromosomes (i.e. paternal and maternal) during gametogenesis. It can occur by following ways
(i) Crossing over Mutual exchange of genes between non-sister chromatids of homologus chromosomes during meiosis-I. It forms multiple variations in a population.
(ii) Independent assortment of chromosomes It forms genetically different haploid gametes during meiosis which bring about variations in new generation.
(iii) Random fusion of gametes During sexual reproduction, random fusion of male and female gametes produces a new individual.

Changes in Chromosome Number and Structure:
Chromosomal mutations or aberrrations arise due to change in number and structure of chromosomes. Chromosomal number may change in followinng two ways
(i) Polyploidy (increase in number of chromosome sets)
(ii) Aneuploidy (change in number of one or both chromosomes of a homologous pair). When the change occurs in the chromosomal morphology, it is called chromosomal aberration.

These are of four types
(i) Deletion Loss of a segment of a chromosome.
(ii) Duplication Doubling of a chromosomal segment.
(iii) Inversion Reversal in the order of genes.
(iv) Translocation Mutual exchange of a segment of chromosome between two non-homologous chromosomes.

Gene Mutations:
In 1901, Hugo de Vries carried out experiments on evening primrose plant (Oenothera lamarckiana) and proposed the mutation theory of evolution. This theory states that the evolution occurs by the sudden large differences or mutations in the population. Mutation is the sudden change in appearance or variations in an individual or a population. When mutation affects only a single nucleotide, it is called point mutation.

However, when more than one nucleotide is involved in mutation, it is called gross mutation. These mutations results in drastic changes which can be lethal or insignificant or useful. They lead to the new phenotypes. Though mutations are random and occur at very slow rates, they are sufficient to create considerable genetic variations for speciation to occur.

Natural Selection:
It is the most widely accepted theory for explaining the mechanism of evolution, profounded by Charles Darwin and Alfred Russel Wallace. Natural selection selects the favourable variation and allows such organisms to reproduce. Meanwhile, harmful or non-adaptive variations are discouraged by natural selection and such organisms are eliminated from the population. Therefore, variations act as raw material natural selection which decides the favourable traits to continue through generations.

Isolation:
The mechanism by which a population gets segregated into two or more subtypes by a geographical barrier, such that each subtype influences a different environment, is called isolation.
This segregation can occur due to
(i) Geographical isolation When two related populations occupy geographically or spatially separated areas.
Such species are called as allopatric species. These species become so different to each other that when they are brought together, they fail to reproduce.
(ii) Reproductive isolation The prevention of interbreeding between the population of two different species. Such reproductively isolated species are called as sympatric species.

Odisha State Board CHSE Odisha Class 12 Biology Solutions Chapter 7 Molecular Basis of Inheritance Textbook Questions and Answers.

CHSE Odisha 12th Class Biology Chapter 7 Question Answer Molecular Basis of Inheritance

Molecular Basis of Inheritance Class 12 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Fill in the blanks with correct answers from the choices given in the brackets of each bit

Question 1.
In split genes, the coding sequences are ……….. (introns, operons, exons, cistrons)
Answer:
exons

Question 2.
The smallest part of the gene is called …………… (recon, muton, exon, cistron)
Answer:
cistron

Question 3.
The enzyme referred to as Kornberg enzyme is ……….. (DNA polymerase-I, DNA polymerase-II, RNA polymerase, ligase)
Answer:
DNA polymerase-I

Question 4.
The polymerase that has 5′-3′ exonuclease property is known as ………… (DNA pol-I, DNA pol-II, RNA pol, DNA ligase)
Answer:
DNA pol-I

Question 5.
The termination factor that recognises the termination codon UAG is ………….. (only RF₁, only RF₂, both RF₁ and RF₂, neither RF₁ and RF₂)
Answer:
Only RF

Question 6.
The enzyme that removes formyl group from the first amino acid methionine of a newly synthesised polypeptide is ………… (RF₃ translocase, deformylase, exoaminopeptidase)
Answer:
deformylase

Question 7.
The word gene was coined by ……….. (Garrod, Johannsen, Meischer, Griffith)
Answer:
Wilhelm Johannsen

Question 8.
In 1869 …………… discovered DNA.(Garrod, Meischer, GrifFith, Wilkins)
Answer:
Friedrich Meischer

Question 9.
The virulent, pneumococcus possessed a …………. coat for its protection. (protein, lipid, phospholipid, polysaccharide)
Answer:
polysaccharide

Question 10.
Complete sequence of amino acids in ………….. was proposed by Sanger. (insulin, haemoglobin, kinetin, polymerase)
Answer:
insulin

Question 11.
RNAs lack ………. as nitrogenous base. (adenine, guanine, cytosine, thymine)
Answer:
thymine

Question 12.
One complet turn of B-DNA contains ………….. number of nitrogenous bases. (10,11,9,12)
Answer:
10 .

Question 13.
The most stable form of RNA is …………. RNA. (messenger, transfer, ribosomal, small nuclear)
Answer:
ribosomal

Question 14.
When a codon codes or more than one amino acid, it is called ………….. code.
(commaless, degenerate, nonsense, universal)
Answer:
degenerate

Question 15.
The start codon is ………… (UAA, UGA, AUG, UGA)
Answer:
AUG

Express in one or two word(s)

Question 1.
If in a double-stranded DNA there is 25% of thymine, then calculate the per cent of guanine.
Answer:
25%

Question 2.
What is the complementary base of adenine in RNA?
Answer:
Uracil

Question 3.
In a double helix if one stand is on 5′ → 3′, what will be arrangement of other strand?
Answer:
3′ → 5′

Question 4.
What are the basic proteins called in eukaryotic DNA?
Answer:
Histones

Question 5.
What is called to amino acids with more than one codon?
Answer:
Degenerate

Question 6.
What type of genes do express continuously ?
Answer:
Housekeeping genes

Question 7.
What type of RNAs do carry amino acids to the site of protein synthesis ?
Answer:
tRNA

Correct the sentences in each bit without changing the underlined words

Question 1.
Watson and Griffith proposed double helical structure of DNA.
Answer:
Watson and Crick proposed the double helical structure of DNA.

Question 2.
A nucleoprotein is building block of all nucleic acids.
Answer:
Nucleotides are the building blocks of all nucleic acids.

Question 3.
The strand of the DNA double helix represent nucleotide phosphate backbone and are antiparallel.
Answer:
The DNA double helix consist of a polynucleotide chain with a backbone formed of sugar and phosphate groups. These chains are antiparellel to each other.

Question 4.
The helical turns are right handed is Z DNA.
Answer:
The helical turns are left-handed in Z-DNA.

Question 5.
Avery, McCarty and MacLeod experimentally proved that the transforming principle is a protein.
Answer:
Avery, McCarty and MacLeod experimentally proved that transforming principle is DNA.

Question 6.
Meischer proposed the transforming principle.
Answer:
Frederick Griffith proposed the transforming principle.

Question 7.
The enzyme ligase is responsible for transcription.
Answer:
The enzyme DNA dependent RNA polymerase is responsible for transcription.

Question 8.
The operator is under the control of a repressor molecule synthesised by structural gene which is not a part of operon.
Answer:
The operator is under the control of a repressor molecule synthesised by regulator gene (i-gene) which is a part of operon.

Question 9.
The example of regulatory gene is genes of respiratory enzymes.
Answer:
The example of constitutive gene is genes of respiratory enzymes.

Question 10.
P-site in prokaryotes only accepts tRNA^met.
Answer:
P-site in prokaryotes only accepts tRNA f^met.

Question 11.
The coding or translatable sequences are introns.
Answer:
The intervening or non-coding sequences are introns.

Question 12.
The structural gens transcribe tRNA and rRNA.
Answer:
The structural gene do not transcribe tRNA and rRNA.

Question 13.
A primer is a small DNA or RNA strand hydrogen bonded to a template.
Answer:
A primer is a short strand of RNA or DNA that serves as a starting point for DNA synthesis.

Question 14.
In DNA replication, as per semiconservative model, two new strands synthesised, form new DNA molecules.
Answer:
In DNA replication as per semiconservative model, two parental strands would separate and act as a template for the synthesis of new complementary strands. Hence, a new strand consist of one parental strand and other new replicated strand.

Fill in the blanks

Question 15.
The enzyme …………. hydrolyses DNA molecules.
Answer:
exonucleases

Question 16.
Clover leaf model of fRNA was proposed by ………………
Answer:
Holey

Question 17.
The segment of DNA that expresses specific character is called …………..
Answer:
gene

Question 18.
The enzyme ………… helps to join nucleotides.
Answer:
ligase

Question 19.
The DNA strand which takes part in transcription is called ………………
Answer:
leading strand

Question 20.
UAG is …………. codon.
Answer:
stop

Question 21.
The gene which becomes active due to the presence of specific substance is called ………….. gene.
Answer:
inducible

Question 22.
To identify criminals DNA ………… is done.
Answer:
fingerprinting

Short Answer Type Questions

Write notes on the following with atleast 2 valid points

Question 1.
Inducible operon
Answer:
Inducible operon An inducible operon is an operon, in which the presence of a key metabolic substance induces transcription of the structural genes. One example of an inducible operon is lac operon and the inducer of this operon is lactose.

Question 2.
Repressible operon
Answer:
Repressible operon A repressible operon is an operon which always transcribes structural genes unless a repressor is present. One example of a repressible operon is trp operon.

Question 3.
Housekeeping genes
Answer:
House keeping genes are involved in basic cell maintenance and therefore are expected to maivlain constant constant expression levels in all cells and conditions. They are also called constituline gene

Question 4.
Adaptor molecules
Answer:
Adapter molecules tRNA acts as adapter molecules in translation. It serves as the physical link between the mRNA and the amino acid sequence of proteins. It carries an amino acid to the ribosome as directed by a three nucleotide sequence in a mRNA.

Question 5.
Split genes
Answer:
Split genes It is an interrupted gene that contains sections of DNA called exons which are expressed as RNA and proteins, interrupted by sections of DNA called introns, which are not expressed.

Question 6.
RNA splicing
Answer:
RNA splicing Splicing is the editing of the nascent precursor of mRNA transcript into a mature mRNA. After splicing, introns are removed and exons are joined together. The process of splicing involves two successive transesterification reaction. The RNA splicing is carried out with the help of a large complex called spliceosome.

Question 7.
Termination of translation
Answer:
Termination:
It is accomplished by the presence of any of the three termination codon on mRNA. Which are recognised by the release (termination) factor, RF₁, RF₂ and RF₃.

RF₁ and RF₂ They resemble the structure of tRNA. They compete with tRNA to bind the termination codon at A-site of ribosome. This is called molecular mimicry. RF₁ recognise UAG and RF₂ recognise UGA. UAA is recognised by both of them. RF₃ helps to split the peptidyl tRNA body by using GTP.
Note In eukaryotes, only one release factor is known. It iseRF₁.

Question 8.
Okazaki fragments
Answer:
Okazaki fragments During DNA replication, the new strand elongation occurs in opposite directions, as the two strands of the DNA are antiparallel.
On the leading strands, a continuous synthesis of new strand occurs while on the other strand (5′ → 3′ strand) discontinuous synthesis occurs. These discontinuous pieces of new DNA strands are called Okazaki fragments which join by DNA ligase to form the continuous strand

Question 9.
Central dogma
Answer:
Central Dogma:
It was proposed by Francis Crick (in 1958). According to the central dogma in molecular biology, the flow of genetic information is unidirectional, i.e.
DNA → RNA → Protein.

Central dogma
But later in 1970, HM Temin reported that the flow of information can be in reverse direction also, i.e. from RNA to DNA in some viruses (e.g. HIV) which is called as reverse transcription.

Modified central dogma

Note: Eukaryotic gene expressions were obtained from yeast,
Arabidopsia thaliana with developed techniques.

Differentiate with atleast 2 valid points

Question 1.
Genes and Chromosomes.
Answer:
Differences between genes and chromosomes are as follows

Genes	Chromosomes
Gene is a segment of DNA on the chromosome that codes for a functional protein and RNAs like tRNA, rRNA or ribozymes.	Chromosome is the structure formed by the condensation of chromatin during cell division.
Genes basically refers to the DNA fragment that directs the synthesis of a protein.	Chromosome consists of long DNA strand wrapped around histone proteins.
Gene contain coding sequence called exons and non-coding sequence called introns on the chromosome that directs synthesis of a protein.	Chromosome is a long DNA strand containing bdth coding (genes) and non-coding DNA (junk DNA or spacer DNA) between genes.

Question 2.
DNA and RNA.
Answer:
Differences between DNA and RNA are as follows

DNA	RNA
It is mainly confined to the nucleus, but also occurs in mitochondria and chloroplasts in small amount.	It mainly occurs in the cytoplasm. A small quantity is found in the nucleus.
It contains deoxyribose.	It contains ribose sugar.
It pyrimidines are cytosine and thymine.	Its pyrimidines are cytosine and uracil.
It consists of two polynucleotide chains held together by hydrogen bonds and coiled into a double helix. Some viruses (ϕ x 174) have single- stranded DNA.	It consists of a single polynucleotide chain. It may fold on itself and get hydrogen bonded and coiled into a pseudohelix. Some viruses (reovirus) have double-stranded RNA.

Question 3.
Purines and Pyrimidines.
Answer:
Differences between purines and pyrimidines are as follows

Purines	Pyrimidines
It contains two carbon-nitrogen rings and four nitrogen atoms.	It contains one carbon nitrogen ring and two nitrogen atoms.
Purines are adenine and guanine	Pyrimidines are cytosine, thymine and uracil.
120.11 g mol molar mass	80.088 g mol<sup>-1</sup> molar mass.

Question 4.
Exons and Introns.
Answer:
Differences between exons and introns are as follows

Exons	Introns
These are the nucleotide sequence of genes that are expressed and those are found at either sides of an intron.	These are sequences of nucleotides present in the genes between exons.
These are nucleotide sequences which code for proteins.	These are nucleotide sequences do not code for proteins.
These are translated regions on mRNA.	These are untranslated regions on mRNA.
After RNA splicing, only exons are present on the mature mRNA.	These are removed from mRNA during RNA splicing.

Question 5.
B-DNA and Z-DNA.
Answer:
Differences between B-DNA and Z-DNA are as follows

B-DNA	Z-DNA
It is with a right-handed type of helix.	It is with a left-handed type of helix.
Its helical diameter is 2.37 nm.	Its helical diameter is 1.84 nm.
It has 0.34 nm rise per base pair.	It has 0.37 nm rise per base pair.
It has 3.4 nm distance per complete turn.	It has 4.5 nm distance per complete turn.
Number of base pair per complete turn are 10.	Number of base pair per complete turn are 12.

Question 6.
Answer:
Replication and Transcription.
Answer:
Differences between replication and transcription are as follows

Replication	Transcription
It occurs in the S-phase of cell cycle.	It occurs in the G<sub>1</sub> and G<sub>2</sub> phases of cell cycle.
It is catalysed by DNA polymerase enzyme.	It is catalysed by RNA polymerase enzyme.
Deoxyribonucleoside triphosphate (dATP, dGTP, dTTP) serve as raw materials.	Ribonucleoside triphosphate (ATP, UTP, GTP, CTP) serve as raw materials.
Replication occurs along the strands of DNA.	IT takes place along one strand of DNA.
It involves unwinding and splitting of the entire DNA molecule.	It involves unwinding and splitting of only those genes which are to be transcribed.
It involves copying of the entire genome.	It involves copying of certain individual genes only.
Two double-stranded DNA molecules are formed from one DNA molecule.	A single one-stranded RNA molecule is formed from a segment of one strand.
Serve to conserve the genome for the next generation of cells and individuals.	Serve to form DNA copies of individual genes for immediate use in protein synthesis.
It require RNA primer to start replication.	No primer is required to start.
It produces normal DNA molecules that do not need	It produces primary RNA transcript molecules which need processing to acquire final form and size.

Question 7.
Transcription and Translation.
Answer:
Differences between transcription and translation are as follows

Transcription	Translation
It is the formation of RNA from DNA.	It is the synthesis of polypeptide over ribosome.
The template is antisense strand of DNA.	The template is mRNA.
It occurs inside the nucleus in eukaryotes and cytoplasm in prokaryotes.	It occurs in cytoplasm.
The raw materials are four types of ribonucleoside triphosphates – ATP, GTP, CTP and UTP.	The raw materials are 20 types of amino acids.
It forms three types of RNAs, i.e. rRNA, tRNA and mRNA	All the three types of RNAs take part in translation.
Transcription requires RNA polymerases and some transcription factors.	Translation requires initiation, elongation and releasing factors.
Polymerase moves over the template DNA.	Ribosome moves over mRNA.
An adapter molecule is not required.	Adaptor molecules bring amino acids over the template.
Product often requires splicing.	Splicing is absent.

Question 8.
Housekeeping gene and Inducible gene.
Answer:
Differences between housekeeping gene and inducible gene are as follows

Housekeeping gene	Inducible gene
These genes are constantly expressing themselves in a cell because their products are required for the normal cellular activities, e.g. genes for glycolysis, ATPase.	These genes are switched on in response to the presence of a chemical substance or inducer which is required for the functioning of the product of gene activity, e.g, nitrate for nitrate reductase.

Question 9.
Degenerate codon and Nonsense codon.
Answer:
Differences between degenerate codon and nonsense codon are as follows

Degenerate codon	Nonsense codon
Genetic code is degenerate for a particular amino acid, that is more than one codon can code for a single amino acid.	A codon for which no normal tRNA molecule exists does not code for any amino acid.
These codon causes translation.	The presence of nonsense codon causes termination of translation ending polypeptide synthesis chain.
These are many e.g. phenylalanine has two Codon is UAA and UUC.	These are three nonsense codons and are called amber(UAG), ochre(UAA) and opal(UGA).

Long Answer Type Questions

Question 1.
Give the structure of DNA. Add a note on different forms of DNA.
Answer:
Primary Structure of DNA:
Two nucleotides when linked through a 3′-5′ phosphodiester linkage, form a dinucleotide. The phosphodiester linkage is formed when each phosphate group esterifies to the 3′ hydroxy group of a pentose and to the 5′ hydroxyl group of the next pentose.

In a similar fashion, more nucleotides may join to form a polynucleotide chain (fig. structure of DNA). The polymer chain thus, formed has
(i) One end with a free phosphate moiety at 5′ end of deoxyribose sugar. This is marked as 5′ end of polynucleotide chain.
(ii) The other end with a free hydroxyl 3′-OH group marked as 3′ end of the polynucleotide chain.
Thus, the sugar and phosphates form the backbone in a polymer chain and the nitrogenous bases linked to sugar moiety project from this backbone. In RNA, there is an additional -OH group at 2′ position in the ribose of every nucleotide residue.

Secondary Structure of DNA:
Watson and Crick proposed the secondary structure in the form of the famous double helix model in 1953 on the basis of following observations
1. Erwin Chargafif (in 1950) formulated important generalisation on the base and other contents of DNA, called as ChargafFs rule. It states that for a double-stranded DNA, the ratios between adenine (A) and thymine (T) and guanine (G) and cytosine (C) are constant and equal to one.
i.e. \(\frac{A + T}{G + C}\) = 1

2. X-ray diffraction studies by Wilkins in 1952, suggested a helicoidal configuration of DNA.

One of the important features of this model was the complementary base pairing. It means if the sequence of bases in one strand is known, the sequence in other strand can be easily predicted. Also, if each strand from a DNA acts as a template for synthesis of a new strand, the daughter DNA thus produced would be identical to the parental DNA molecule.

Watson and Crick Model of DNA:
Watson and Crick worked out the first correct double helix model of DNA, which explained most of its properties.
The salient features of double helix structure of DNA are as follows
(i) DNA is made up of two polynucleotide chains. The backbone is constituted by sugar phosphate, while the nitrogenous bases project inwards.
(ii) The two chains have anti-parallel polarity, i.e. when one chain has 3′ → 5′ polarity, the other has 5′ → 3′ polarity. Hence, orientation of deoxyribose sugar is opposite in both the strands.
(iii) The two strands are complementary to each other, i.e. purine base of one strand has pyrimidine counterpart on other strand. The complementary bases in two strands are paired through hydrogen bonds (H-bonds) to form base pairs.
(a) Adenine is bonded with thymine of the opposite strand with the help of two hydrogen bonds.
(b) Guanine is bonded with cytosine of the opposite strand with the help of three hydrogen bonds. So, a purine bonds with a pyrimidine always. Thus, maintaining a uniform distance between the two strands of the helix.
(iv) The two polypeptide chains are coiled in a right-handed fashion. Pitch of the helix, i.e. length of DNA in one complete turn = 3.4 nm or
3.4 × 10^-9 or 34 Å.
Number of base pairs in each turn = 10. Distance between a base pair in a helix = 0.34 nm. The diameter of DNA molecule is 20 Å (2nm).
(v) Percentage calculation of bases is done by
A + T = 100 – (G + C).
(vi) The plane of one base pair stacks over the other in double helix. This provides the stability to the helical structure, in addition to H-bond.
The length of DNA in E. coli is 1.36 mm, while in humans it is 2.2 m.

Structure of DNA : (a) Watson and Crick model of double helix, (b) Double-stranded polynucleotide chain sequence showing hydrogen bonds

Structural Forms of the Double Helix:
Double helical DNA exists in three structural forms namely the A-form DNA, the B-form DNA (described by Watson and Crick) and the Z-form DNA. The transition among these three forms plays an important role in the regulation of gene expression.
(i) B-DNA It is right-handed helix, contains 10 residues per 360° turn.

• The planes of bases are perpendicular to the helix axis.
• It is primarily found in chromosomal DNA.

(ii) A-DNA

• It is formed by the moderate dehydration of B-DNA.
• It is right-handed helix, contains 11 base pairs (residues) per 360° turn.
• The planes of bases are tilted 20° away from the perpendicular to helical axis.
• It is mainly found in DNA-RNA hybrid or RNA-RNA double-stranded regions.

(iii) Z-DNA It has zig-zag backbone and hence has the name.

• It is a left-handed helix, twelve base pairs are present per turn.
  
• The Z-DNA stretches occurring naturally in DNA have a sequence of alternating purines and pyrimidines (i.e. poly GC regions).
• Besides these three major forms, the other two right-handed forms are
  • C-DNA with nine base pairs per turn.
  • D-DNA with eight base pairs per turn. There are many forms of DNA molecules in viruses.

Various Forms of DNA Molecules Found in a Variety of Viruses

Question 2.
Describe the semiconservative model of DNA replication.
Answer:
DNA Replication
In addition to the double helical structure of DNA, Watson and Crick also proposed a scheme for DNA replication. According to this model, the two strands of double helix separate and act as a template for the synthesis of new complementary strands in which the base sequence of one strand determines the sequence on the other strand.

This is called base complementarity and it ensures the accurate replication of DNA. After the completion of replication, each DNA molecule have one parental and one newly synthesised strand.
This scheme for DNA replication was termed as semiconservative DNA replication.

DNA Replication is Semiconservative:
Matthew, Meselson and Franklin Stahl in 1958 conducted an experiment in California Institute of technology with Escherichia coli to prove that DNA replicates semiconservatively as follows

1. They grew many generations of E.coli in a medium containing ¹⁵NH₅Cl (¹⁵N is the heavy isotope of nitrogen) as the only source of nitrogen.
The result was that ¹⁵N got incorporated into the newly synthesised DNA after several generations. By centrifugation in a cesium chloride (CsCl) density gradient, this heavy DNA molecule could be distinguished from the normal DNA.

2. The bacterial culture was then washed to make the medium free and the cells were then transferred into a medium containing normal ¹⁴NH₄Cl.

3. The samples were separated independently on CsCl gradient to measure the densities of DNA.

4. At definite time intervals, as the cells multiplied, samples were taken and the DNA which remained as double-stranded helices was extracted.

5. The DNA obtained from the culture, one generation after the transfer from ¹⁵N to ¹⁴N medium (i.e. after 20 minutes because E.coli divides in 20 minutes) had a hybrid or intermediate density.
This hybrid density was the result of replication in which DNA double helix had separated and the old strand (N¹⁵) had synthesised a new strand (N¹⁴).

6. The DNA obtained from the culture after another generation (II generation) was composed of equal amounts of hybrid DNA containing (N¹⁵ molecule) and ‘light’ DNA (containing 4 N molecule).

7. With the preeceding growth generations in normal medium, more and more light DNA was present. Hence, the semiconservative mode of DNA replication was confirmed.

Meselson-Stahl experiment to demonstrate semiconservative replication

were conducted by Taylor and colleagues in 1958, involving use of radioactive thymidine, i.e. bromodeoxy-uridine. The replicated chromosomes were then, stained with fluorescent dye and Giemsa. The old and new strand were stained differently which confirm that the DNA in chromosomes also replicates semiconservatively.

Question 3.
Give evidences of DNA as genetic material.
Answer:
DNA as Genetic Material:
The discovery of nuclein by Meischer and the proposition of principal of inheritance by Mendel were almost at the same time, i.e. 1869 and 1866, respectively. But the fact that DNA acts as a genetic material took a long time to be discovered and proven.

By 1926, the quest to determine the mechanism for genetic inheritance had reached the molecular level and gradually the question, what molecule acts as genetic material got answered.

Transforming Principle:
Frederick Griffith in 1928, carried out a series of experiments with Diplococcus pneumoniae (a bacterium that causes pneumonia). He observed that when these bacteria were grown on a culture plate, some of them produced smooth, shiny colonies (S-type), whereas the others produced rough colonies (R-type).

This difference in appearance of colonies (smooth/rough) is due to the presence of mucous (polysaccharide) coat on S-strains (virulent/pathogenic) but not on R-strains (avirulent/non-pathogenic).

Experiment:

• He first infected two separate groups of mice. The mice that were infected with the S-strain (S-III) died from pneumonia as S-strains are the virulent strains causing pneumonia.
• The mice that were infected with the R-strain (R-II) did not develop pneumonia and they lived.
• In the next set of experiments, Griffith killed the bacteria by heating them. The mice that were injected with heat-killed S-strain bacteria did not die and lived.
• Whereas, on injecting a mixture of heat-killed S-strain and live R-strain bacteria, the mice died. Moreover, living S-bacteria were recovered from the dead mice.
  These steps are summarised below
  

From all these observations Griffith concluded that the live R-strain bacteria, had been transformed by the heat-killed S-strain bacteria, i.e. some ‘transforming principle’ had transferred from the heat-killed S-strain, which helped the R-strain bacteria to synthesise a smooth polysaccharide coat and thus, become virulent.

This must be due to the transfer of the genetic material. However, he was not able to define the biochemical nature of genetic material from his experiments.

Biochemical Characterisation of Transforming Principle:
Oswald Avery, Colin MacLeod and Maclyn McCarty (1933-44) worked in Rockfellar Institute, New Xork, USA to determine the biochemical nature of ‘transforming principle’ in Griffith’s experiment in an in vitro system. Prior to this experiment, the genetic material was thought to be protein.

During this experiment, purified biochemicals (i.e. proteins, DNA, RNA, etc.) from the heat-killed S-III cells were taken, to observe which biochemicals could . transform live R-cells into S-cells.

They discovered that DNA alone from heat-killed S-type bacteria caused the transformation of non-virulent R-type bacteria into S-type virulent bacteria.
They also discovered that protein digesting enzymes (proteases) and RNA digesting enzymes (ribonuclease) did not inhibit this transformation. This proved that the ‘transforming substance’ was neither protein nor RNA.

DNA-digesting enzyme (deoxyribonuclease) caused inhibition of transformation, which suggests that the DNA caused the transformation. This provided the first evidence for DNA as transforming principle or the genetic material.

The steps of this experiment are summarised below:

1. R-II + DNA extract of S-III + no enzyme = R-II colonies + S-III colonies
2. R-II + DNA extract of S-III + Ribonuclease = R-II colonies + S-III colonies
3. R-II + DNA extract of S-III + Protease = R-II colonies + S-III colonies
4. R-II + DNA extract of S-III + Deoxyribonuclease = Only R-II colonies

Question 4.
Explain the mechanism of translation in prokaryotes.
Answer:
Mechanism of Translation:
The main steps in translation include
(i) Binding of iwRNA to ribosome
(ii) Activation of amino acids (aminoacylation of rRNA).
(iii) Transfer of activated amino acids to rRNA.
(iv) Initiation of polypeptide chain synthesis.
(v) Elongation of polypeptide chain.
(vi) Termination of polypeptide chain formation.

(i) Binding of mRNA to Ribosome
Ribosomes occur in the cytoplasm as separate smaller and larger units.
In prokaryotes, IF-3 binds to 30 S subunit to prevent association of subunits. The incoming tRNA containing specific amino acid binds to the A-site. The prokaryotic mRNA has a leader sequence called shine-Delgarno sequence that is present just prior to initiation codon-AUG.

It is homologous to 3′ end of 16S rRNA (ASD region) in 30S subunit. This complementarity ensures correct binding of 30S subunit on mRNA. The peptidyl mRNA containing elongating polypeptide then binds to P-site.
The bacterial ribosome contains another site, the E-site or Exit-site to which the discharged tRNA or tRNA whose peptidyl has already been transferred binds before its release from ribosome.

A bacterial ribosome with three sites; E, exit site, P, peptidyl site and A, aminoacyl site

(ii) Aminoacylation
Aminoacylation of tRNA The activation of amino acids takes place through their carboxyl groups. The amino acids are activated in the presence of ATP and linked to their cognate tRNA. In the presence of ATP, amino acids become activated by binding with aminoacyl tRNA synthetase enzyme.

The amino acid AMP-enzyme or AA-AMP enzyme complex is called an activated amino acid.
In the second step, this complex associated with the 3′-OH end of tRNA. AMP gets hydrolysed to form an ester bond between amino acid and tRNA and the enzyme is released.
AA – AMP – enzymes + tRNA ——– AA – tRNA + AMP + enzyme.

(iii) Transfer of Activated Amino Acids to tRNA:
The amino acids are attached to the tRNA by high energy bonds. These bonds are formed between the carboxyl group of amino acid and 3′ hydroxy terminal of ribose of terminal adenosine of CCA and of tRNA.
The complete reaction is carried out by enzyme synthetase which has two active sites, i.e. one for rRNA and another for specific amino acid molecule.

(iv) Initiation of Polypeptide Chain Synthesis:
The protein synthesis begins from the amino terminal end of the polypeptide, proceeds by the addition of amino acids through peptide bond formation and ends at the carboxyl terminal end. In prokaryotes, the initiation amino acid is formylated methionine while in eukaryotes it is methionine.
Initiation in Prokaryotes
In prokaryotes, two types of tRNA are present for methionine

• tRNAf^met for initiation carrying formyl methionine and
• tRNA^met for carrying normal methionine to growing polypeptide.

The initiation of polypeptide synthesis requires the following components
mRNA, 30S subunit of ribosome, formylmethionyl-tRNA (f^met – tRNAf^met), initiation factors IF-1, IF-2 and IF-3, GTP, 50S ribosomal subunit and Mg⁺².

The sequence of events occurring during initiation process are

1. The smaller 30S subunit of ribosome binds to the transcription factor IF-3. It prevents the premature association of two ribosomal subunits.

2. Interaction of SD region of mRNA and ASD region of ribosome helps the mRNA to bind to 30S subunit. It also helps AUG to correctly positioned at the P-site of the ribosome.

3. The fMet-tRNAf^met (the specific tRNA aminoacylated to formyl methionine) binds to the AUG codon at the P-site. The tRNAf^met is the only tRNA that binds to its codon present on the P-site. All other tRNA along with their respective amino acids bind to their codon present at the A-site. Therefore, AUG codon present as initiation codon codes for formylmethionine. When it is present at other position it codes for normal methionine.

4. The initiation factor IF-1, binds to the A-site. It prevents the binding of any other aminoacyl tRNA to the codon at the A-site during initiation.

5. The GTP bound IF-2 (GTP-IF-2) and the initiating f Met-tRNAf^met attaches to the complex of 30S subunit-IF3-IF1-mRNA.

6. 50S subunit then attaches the complex formed in the previous step. The GTP bound to IF-2 is hydrolysed to GDP and Pi. After this step, all the three initiation factors leave ribosome. This complex of 70S ribosome, mRNA and f Met-tRNA f^met bound to initiation codon at P site is known as initiation complex.

Stepwise formation of initiation complex in prokaryote

(v) Elongation of Polypeptide Chain:
In this step, another charged aminoacyl tRNA complex binds to the A-site of the ribosome, following the hydrolysis of GTP to GDP and Pi. A peptide bond forms between carboxyl group (—COOH) of amino acid at P-site and amino group (—NH₃) of amino acid at A-site by the enzyme peptidyl transferase.

Binding of the second aminoacyl tRNA to the A site of ribosome

Formation of a peptide bond

(vi) Translocation of Polypeptide:
The peptidyl fRNA bounded to A-site comes to the P-site of ribosome.
The empty tRNA comes to E-site and a new codon occupies the A-site for next aminoacyl tRNA.

• This is achieved by the movement or translocation of ribosome by a codon in 5′ to 3′ direction of mRNA in the presence of EF-G (translocase) and GTP.
• tRNA interact with E-site on 50S subunit through it CCA sequence at 3′ end.

The tRNA molecule is then, transferred from A site to P-site and from P-site to E-site by the movement of two subunits of ribosomes.
Finally, the deacylated tRNA is released to cytosol from E-site.

(vii) Termination:
It is accomplished by the presence of any of the three termination codon on mRNA. Which are recognised by the release (termination) factor, RF₁, RF₂ and RF₃.

RF₁ and RF₂ They resemble the structure of tRNA. They compete with tRNA to bind the termination codon at A-site of ribosome. This is called molecular mimicry. RF₁ recognise UAG and RF₂ recognise UGA. UAA is recognised by both of them. RF₃ helps to split the peptidyl tRNA body by using GTP.

Question 5.
Describe transcription in prokaryotes.
Answer:
Transcription in Prokaryotes:
All three RNAs are needed for synthesis of a protein in a cell. DNA dependent RNA polymerase is the single enzyme that catalyses the transcription of all types of bacterial RNA. But for the expression of different genes, different sigma factors may associate with same core enzymes.

In E.coli, σ⁷⁰ is used in normal condition σ³² / σ^H under heat shock, σ⁵⁴ /σ^N under nitrogen starvation and σ²⁸ for chemotaxis.

A typical bacterial transcription unit

The transcription process in prokaryotes occurs in following steps
I. Initiation

1. The holoenzyme binds to the promoter region of transcription unit.
2. The sigma polypeptide binds loosely to the promoter sequences so as to form a loose, closed, binary complex.
3. It is followed by the formation of a transcription eye or bubble due to the denaturation of adjacent sequence of DNA, lying next to the complex.
4. The transcription bubble along with the bounded holoenzyme is called open binary complex.
5. In 90% of cases, the start point of transcription is a purine.
6. At the elongation site of enzyme, two nucleotides complementary to the first two nucleotides of template strand binds.
7. A phosphodiester bond is formed between these two ribonucleotides.
8. At this stage, the complex is called ternary complex that consists of partly denatured DNA bounded with holoenzyme having a di-ribonucleotide.
9. The same process continues till a RNA chain of about nine nucleotides is synthesised. The holoenzyme does not move throughout this process.
10. After the completion of initiation process, sigma factor dissociates from RNA polymerase. This facilitates the promoter clearance so that a new holoenzyme can bind to promoter for second round of transcription.
    
    Binding of RNA polymerase and initiation of RNA synthesis

II. Elongation

• The RNA chain grows in 5′-3′ direction by the addition of ribonucleotides to the 3′-end of RNA.
• The transcription bubble moves in 3′ → 5′ direction of template strand.
• The movement of holoenzyme along the bubble unwinds (denature) the DNA in growing point and rewinds at the opposite end.
• In each elongation cycle, the growing site (leading product) of enzyme gets filled with 10 newly added nucleotides. The opposite site (lagging product) contains the previous segment of RNA.
• About 40 nucleotides are added per 37°C.
• In some phages, e.g. T₃ and T₄, RNA pol synthesise RNA at much rapid rate of about 200 nucleotides per 37° C.
  
  Elongation of RNA chain by the movement of RNA polymerase and transcription bubble in 5′ to 3′ direction

III. Termination
It is achieved by certain termination signals on DNA called terminators. In E.coli, terminators are of two types

(a) Intrinsic Terminators

• These are rho independent protein factors in which the RNA at 3′-end contains a long stretch of U residues.
• These residues are hydrogen bonded to the long stretch of A residues of the temple. In the stem of the RNA, a stretch of G-C rich segment is present which results in a hair-pin loop formation in the RNA stem.
• Due to the weak association between A-U base pairs, the long stretch of termination sequence break and the RNA is released.
• It occurs due to the formation of hair-pin loop in the stem of RNA before the termination signal slows down transcription and as a result dA-rU bonds break at any one point so as to release RNA from RNA-DNA hybrid.

(b) Extrinsic Terminator

• These are rho dependent protein factors and are extensively used in E. coli.
  This protein is active as an hexamer (having six identical subunits). Its molecular weight is about 46,000 and it also has ATP hydrolysing activity.
• To terminate the process of transcription, rho factor binds to the 5′-end of nascent mRNA and moves along the length of mRNA until it reaches the termination point. Due to this, the transcription process slows down, rho breakdown ATP and utilises the energy to denature the RNA-DNA hybrid. Hence, the RNA is released from the bubble.

In prokaryotes (bacteria), mRNA does not require any processing to become active and both transcription and translation take place in same compartment (as there is no separation of nucleus and cytosol in bacteria). Therefore, translation can start much before the mRNA is fully transcribed, i.e. transcription and translation can be coupled.

Question 6.
Give an account of the operon model.
Answer:
The Operon Model:
F Jacob and J Monod gave the operon concept and were the first ones to describe a transcriptionally regulated system. An operon is a unit of prokaryotic gene expression which includes sequentially regulated (structural) genes and control elements recognised by the regulatory gene product. The various components of an operon are

1. Structural genes These are the regions of DNA which transcribe wRNA for polypeptide synthesis.
2. Promoter gene This is the sequence of DNA where RNA polymerase binds and initiates transcription.
3. Operator This is the sequence of DNA found adjacent to promoter where specific repressor protein binds. It is under the control of a repressor.
4. Regulator It is the gene which codes for the repressor protein binding to the operator and suppresses its activity, so that transcription does not occur. It is also represented as ‘i’ gene. It is synthesised by a regulator gene which is not a part a operon.
5. Inducer Its main role is to prevent the repressor from binding to the operator. This makes the process of transcription to switch on. An inducer can be any metabolite, hormone, etc.

Loc Operon in E. coli:
The lac operon found in E.coli is an inducible system. It is responsible for the synthesis of enzymes found in lactose (the milk sugar). It has an operator sequence of 26 base pairs and three structural genes. Its first structural gene (SG) is lac Z which is of 3063 base pairs. It is responsible for the synthesis of the emzyme ß-galactosidase.

The operator is a part of lac Z. The other two genes are lac y (helps in the synthesis of ß-galactoside permease) and lac a (synthesise fbgalactoside transacetylase). ß-galactoside permease is a transmembrane protein that pumps galactose into the cell, ß-galactosidase helps to breakdown lactose to galactose and glucose.

When lactose is available to the bacterium, the active repressor produced by the regulator forms an inactive dimer with lactose (acts as an inducer).

As a result, the inactive dimer cannot bind to the operator and the three contiguous structural genes are transcribed into a polycistronic or polygenic mRNA which is then translated into three proteins (enzymes). In the absence of lactose (the inducer), the product of regulator enzyme activates inhibitor dimer that, binds to the operator and prevents transcription.

Odisha State Board CHSE Odisha Class 12 Biology Solutions Chapter 6 Sex Determination Textbook Questions and Answers.

CHSE Odisha 12th Class Biology Chapter 6 Question Answer Sex Determination

Sex Determination Class 12 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Choose the correct option

Question 1.
A cross between Fj-hybrid and a recessive parent gives the ratio of
(a) 3 : 1
(b) 2 : 1
(c) 1 : 1
(d) 4 : 1
Answer:
(c) 1 : 1

Question 2.
A cross of F₁ with the recessive parent is known as
(a) back cross
(b) test cross
(c) hybrid cross
(d) double cross
Answer:
(b) test cross

Question 3.
A woman with albinic father marries an albinic man. The proportion of her progeny is
(a) 2 normal : 1 albinic
(b) all normal
(c) all albinic
(d) 1 normal : 1 albinic
Answer:
(d) 1 normal : 1 albinic

Question 4.
Y-chromosome is called
(a) sex chromosome
(b) androsome
(c) autosome
(d) gynosome
Answer:
(a) sex chromosome

Question 5.
Which one is a sex-linked disorder?
(a) Leukemia
(b) Cancer
(c) Night blindness
(d) Colour blindness
Answer:
(d) Colour blindness

Question 6.
A haemophilic man marries a normal homozygous woman. What is the probability that their son will be haemophilic?
(a) 100%
(b) 75%
(c) 50%
(d) 0%
Answer:
(d) 0%

Question 7.
What is the probability that their daughter will be haemophilic?
(a) 100%
(b) 75%
(c) 50%
(d) 0%
Answer:
(d) 0%

Question 8.
A fruitfly exhibiting both male and female trait is
(a) heterozygous
(b) gynandromorph
(c) hemizygous
(d) gynandev
Answer:
(b) gynandromorph

Question 9.
Genes located on Y-chromosome are
(a) mutant genes
(b) autosomal genes
(c) holandric genes
(d) sex-linked genes
Answer:
(c) holandric genes

Question 10.
A colourblind person cannot distinguish
(a) all colours
(b) red colour
(c) green colour
(d) red and green colours
Answer:
(d) red and green colours

Question 11.
The gene responsible for haemophilia is linked to which chromosome?
(a) X
(b) Y
(c) Both X and Y
(d) Autosome
Answer:
(a) X

Question 12.
Red-green colour blindness in man is
(a) sex-linked character
(b) sex-limited character
(c) sex influenced character
(d) sexual character
Answer:
(a) sex-linked character

Question 13.
Sex-linked characters are
(a) dominant
(b) recessive
(c) lethal
(d) not inherited
Answer:
(b) recessive

Question 14.
Which gene is present in the Y-chromosome that codes for the protein TDF?
(a) cry
(b) sty
(c) try
(d) tra
Answer:
(b) sty

Question 15.
In birds, which type of chromosomal basis of sex-determination is present?
(a) XX – XY
(b) XX – XO
(c) ZW – ZZ
(d) ZZ – ZO
Answer:
(c) ZW – ZZ

Question 16.
When the ratio of X/A=0.67 in genic balance theory, which type of sex is expressed?
(a) Super female
(b) Intersex
(c) Super male
(d) Triploid female
Answer:
(b) Intersex

Question 17.
Which type of sex-determination is found in Bonellia?
(a) Temperature dependent
(b) Chemotactic
(c) Holandric
(d) Pseudoautosomal
Answer:
(b) Chemotactic

Question 18.
In a person with Turner syndrome, the number of X-chromosome is
(a) 1
(b) 2
(c) 3
(d) 0
Answer:
(a) 1

Question 19.
A Down syndrome will be
(a) 45 + XX
(b) 44 + XY
(c) 44 + XXY
(d) 22 + XY
Answer:
(a) 45 + XX

Question 20.
Number of Barr bodies present in Turner syndrome is
(a) 0
(b) 1
(c) 2
(d) Either (b) or (c)
Answer:
(a) 0

Express in one or two word(s)

Question 1.
Name two sex-linked diseases of human being.
Answer:
Haemophilia and colour blindness.

Question 2.
How Down’s syndrome is caused?
Answer:
Down’s syndrome is caused due to the presence of an extra-chromosome number 21, i.e. 21 trisomy.

Question 3.
In which chromosome is the gene for haemophilia located?
Answer:
X-chromosome

Question 4.
What is the chromosomal formula for Turner’s syndrome?
Answer:
44 + XO

Question 5.
Which sex is usually a carrier?
Answer:
Female sex

Question 6.
Who proposed the genic balance theory?
Answer:
Calvin Bridges

Question 7.
What are holandric genes?
Answer:
Genes located on Y-chromosomes are known as holandric genes

Question 8.
In which chromosome, the factors for haemophilia and colour blindness are found?
Answer:
X-chromosome

Question 9.
What is the other name of Bleeder’s disease?
Answer:
Haemophilia

Question 10.
Which protein is in sry gene of Y-chromosome?
Answer:
TDF (Testis Determining Factor)

Question 11.
What is gynandromorph?
Answer:
Exhibiting both male and female characters are called gynandromorphs.

Question 12.
What is freemartin?
Answer:
Sterile female with many male characteristics.

Question 13.
What is criss-cross inheritance?
Answer:
The transmission of characters from grandfather to grandson through daughter is called criss-cross inheritance.

Question 14.
Which type of defect is found in thalassemia?
Answer:
The mutation or deletion of the genes controlling the formation of globin chains of haemoglobin result in an abnormal form of haemoglobin.

Question 15.
Who first described Klinefelter’s syndrome?
Answer:
H. F. Klinefelter in 1942.

Short Answer Type Questions

Write brief notes on the following (within 50 words each)

Question 1.
Criss-cross inheritance
Answer:
The transmission of characters from grandfather to grandson through daughter is called criss-cross inheritance.

Question 2.
Holandric gene
Answer:
Genes located on Y-chromosomes are known as holandric genes

Question 3.
Haplo-diploidy mechanism of sex-determination
Answer:
Haplo-Diploidy Mechanism:
In insects-like honeybees wasps, ants, etc., the sex chromosomes are not differentiated and sex is determined on the basis of ploidy of the individual. In honeybees, drones are males and are haploid (n =16), which had developed from unfertilised eggs of females (Arrhenotoky).

Question 4.
Genic balance theory
Answer:
Genic Balance Mechanism
The investigations on Drosophila by C. Bridges showed that female determiners were located on the X-chromosomes and that of male were on the autosomes. Hence, autosomes also plays an important role in determining sex in Drosophila melanogaster. Genic balance’ theory by Bridges proposed the sex-determination mechanism based on the ration of number of X-chromosomes (X) and sets of autosomes (A).

Question 5.
Freemartin
Answer:
It is an infertile female mammal with masculinised behaviour and non-functioning ovaries. Freemartinism is the normal outcome of mixed sex twins in all cattle species, i.e. it occurs when the twins of opposite sex are born also occurs occasionally in other mammals including sheep, goats and pigs.

In most cattle twins, the blood vessels in the chorions become interconnected, creating a shared circulation for both twins. Mostly the male hormones are produced first. If both foetuses are of the same sex this is of no significance, but if they are of different sex, male hormones pass from the male twin to the female twin.
The male hormones then masculinise the female twin and the result is a freemartin or sterile masculine female.

Question 6.
Gynandromorph
Answer:
Abnormal chromosomal behaviour in insects can result in the formation of gynandromorphs or sexual mosaics in which some parts of the animal exhibit female characters and other parts exhibit male characters.

Some gynandromorphs in Drosophila are bilateral intersexes with male colour pattern, body shape, and sex comb on one half of the body and female characteristics on the other half.

The failure of segregation (non-disjunction) of X-chromosomes at cleavage leads to formation of gynandromorphs. The chromosome complement of zygote is 2A + 2X. During first cleavage, one of the X-chromosomes is lost in one of the blastomeres.
As a result, one of the blastomeres acquires 2A + 2X complement which forms the female half while the other blastomere with 2A + X complement forms the male half. Thus, half of the body is female while the other half is male.

Question 7.
Single gene effect
Answer:
Single Gene Effect:
In certain organisms-like Drosophila, human, Asparagus and several fishes, a single gene pair is responsible for the determination and expression of sex.
In Drosophila, the sex is expressed by a recessive gene called tra (transformer) present on the third autosome. Males and female members with dominant (tra+) allele are mostly fertile. However, a normal female (i.e. AA + XX), having homozygous recessive tra alleles, develops into sterile male.

As studied earlier, in humans, the Y-chromosome has a sry gene which influences the development of testis in males. Its absence results in development of ovaries in females.
Thus, an XX female with sry gene or an XY male without sry gene ultimately develops into a sterile female.

Question 8.
Sex reversal
Answer:
Sex Reversal:
Artificial removal of gonads of either sex before puberty (castration or ovariectomy) results in the development of secondary sexual characters of the opposite sex. It is observed in fishes, amphibians, birds and some mammals, including humans.

In the given figure, the hen develops male secondary sex characteristics after the removal of ovaries. Thus, the bird is still female genotypically but phenotypically it becomes male.

Question 9.
Temperature dependent sex-determination
Answer:
Temperature Dependent Sex-Determination:
In some reptiles, the temperature at which the fertilised eggs are incubated prior to hatching plays a major role in determining the sex of the offspring. Surprisingly high temperature during incubation have opposite effect on sex-determination in different species.

In turtles, high incubation temperature (above 30°C) of eggs results in the production of female progeny whereas in the lizard and crocodiles, high incubation temperature results in the production of male offspring. At the lower temperature range between 22.5-27°C, male turtles are produced. This pattern is reversed in lizards and crocodiles.

Question 10.
Chemotactic sex-determination
Answer:
Chemotactic Sex-Determination:
It is seen in males of the marine worm Bonellia. These are small, degenerate and live within the reproductive tract of the larger female. All organs of male worm’s body are degenerate except those of the reproductive system.
In Bonellia, the larvae of male and female are genetically and cytolosically similar, i.e. it is hermaphrodite. A newly hatched worm if reared from a single cell kept in isolation, it develops into a female. If the larvae are reared with mature females in water, they adhere to the proboscis.

Later they transform into males who eventually migrate into the female reproductive tract, where they become parasitic.
It has been found that a chemotactic substance secreted by the proboscis of a mature female Bonellia induces the differentiation of larva into males.

Question 11.
Thalassemia
Answer:
It is an autosomal recessive blood disease, which is caused due to reduced synthesis of either the α or ß-chains of haemoglobin, as a result of mutation in the genes of α or ß-chains. It was discovered by Cooley (1925) and is prevalent in Asia, middle-East, Africa and Mediterranian countries. Anaemia is the characteristic symptom of this disease. Depending upon the globin chain affected, thalassemia is classified into following types, i.e.
1. α-Thalassemia is caused by defective α-chain. The OC-globin is controlled by two genes present on chromosome 16, i.e. HBA1 and HBA2. α-thalassemia is of two types-haemoglobin H-disease and Hydrops Foetalis. The later is more severe as all the four globin genes are mutated and the defective alleles kill the foetus resulting in still birth or death soon after delivery.
Haemoglobin H-disease occurs when there are three defective alleles out of four α-globin genes.

2. ß-Thalassemia is caused by decreased synthesis of ß-globin chain. It is further classified into thalassemia major (Cooley’s anaemia), i.e. when both the alleles for ß-globin are defective or absent. It is more severe in comparison to the second type called thalassemia intermedia, i.e. when only one allele is defective in ß-globin.

Symptoms:
The common symptoms include tiredness, pale skin with severe anaemia, enlarged spleen, yellowish skin and dark urine.

Diagnosis Treatment and Prevention:
The disease is diagnosed by blood test and genetic analysis. There are two treatment options, i.e. blood transfusion and bone marrow transplantation. Genetic councelling is not recommended as it makes the persqn concious about the consequences of the disease.

Question 12.
Down’s syndrome
Answer:
Down’s Syndrome (Mongolism):
This syndrome was previously called mongolism because the affected persons were of short stature. The estimated frequence of birth of individual with Down’s syndrome is 1/700.
It was described by J Langdon Down in 1866 but its cause was found by Lejeune in 1959.

Genetic Basis:
It occurs due to chromosomal aberration, known as aneuploidy (trisomy). The individuals suffering from Down’s syndrome posses an extrachromosome number 21. Both the chromosomes of 21 position passes into a single egg due to primary non-disjunction which may occur during meiosis-I or II in maturation phase of gametogenesis. Thus, the egg instead of possessing 23 chromosomes have 24 chromosomes and the offspring has 47 chromosomes (45 + XY in males, 45 +XX in females). It is also seen in chimpanzees and other related primates.

Question 13.
Turner’s syndrome
Answer:
Turner’s Syndrome:
This condition is characterised by one missing X-chromosome which result in 45 + XO chromosomal complement in affected person. It was first described by H.H. Turner in 1938. The estimated birth frequency of Turner’s syndrome is 1/2500 live female births. It total frequency in human population is 1/5000.

Genetic Basis:
It is a disorder which is caused due to chromosomal aberration, known as aneuploidy (monosomy). Due to absence of one of the X-chromosome, the condition is 45 with XO. Primary non-disjunction in either of meiotic divisions during gametogenesis results in this condition.

Question 14.
Klinefelter’s syndrome
Answer:
Klinefelter’s Syndrome:
HF Klinefelter first described this condition in 1942.
This genetic disorder occurs due to the presence of an additional copy of the X-chromosome. It is also known as trisomy of X-chromosome. Its estimated birth frequency is 1/500 live male births.

Genetic Basis:
The union of an abnormal XX-egg with a normal Y-sperm or a normal X-egg with an abnormal XY-sperms results in the karyotype of 47, XXY in males or 47, XXX in females.

The abnormal eggs and sperms are formed due to the v primary non-disjunction ofX and Y chromosomes during the maturation phase of gametogenesis. Although the usual karyotype of this condition is 47 + XXY but sometimes more complex karyotypes also occurs, e.g. XXXY, XXXXY, XXXXXY, XXXXYY, etc.

Differentiate between two words in the following pairs of words

Question 1.
Phenotype and Genotype.
Answer:
Differences between phenotype and genotype are as

Phenotype	Genotype
It refers to observable traits or characters.	It refers to the genetic constitution of an individual.
It results from expression of genes.	It constitutes single gene pair or sum total of all the genes.
The phenotypic ratio of Mendel’s monohybrid cross is 3 : 1.	The genotypic ratio of Mendel’s monohybrid cross is 1 : 2 :1.
It may change with age and environment.	It remains the same throughout the life of an individual.

Question 2.
Autosome and Allosome.
Answer:
Differences between autosomes and allosomes are as follows

Autosome	Allosomes
They are somatic chromosomes which control the body character  or somatic characters.	They are sex chromosomes which determine the sex of an individual.
In humans, out of the total 23 pairs, of chromosomes 22 pairs are autosomes.	In humans, the 23rd pair of chromosome is called sex  chromosome.

Question 3.
X-chromosome and Y-chromosome.
Answer:
Differences between X and Y-chromosomes are as follows

X-chromosome	Y-chromosome
It is sex chromosome.	It is also a sex chromosome.
Females have two X-chromosomes.	It is absent in females.
It is larger than Y-chromosome.	It is smaller than X-chromosome.
It does not contain sry gene.	It carries male determining gene called sry gene.

Question 4.
Supermale and Superfemale.
Answer:
Differences between superfemales and supermales are as follows

Superfemales	Supermales
Such individuals have 47(44 + XXX), 48(44 + XXX) chromosomes.	Such individuals have 47(44+YYY) chromosomes.
These females have abnormal sexual development and mentally retarded.	These males are characterised by abnormal height, mental retardation.

Question 5.
Sex differentiation and Sex reversal.
Answer:
Differences between sex differentiation and sex reversal are as follows

Sex differentiation	Sex reversal
It is the process of the differences between males and females from an undifferentiated zygote.	It is the phenomenon of development of secondary sexual characters of the opposite sex.
It is induced by specific genes by hormones and by anatomy.	It is induced by some chemicals.

Question 6.
Gynandromorph and Freemartin.
Answer:
Differences between gynandromorphs and freemartin are as follows

Gynandromorphs	Freemartin
It is the phenomenon in which a part of the body exhibits female characters, while the other part exhibits male characters, e.g. Drosophila.	When the,twins of the opposite sex are born, the male is normal but the female is sterile with many male characters. Such sterile females are called freemartin, e.g. cattle.
These develop due to failure of segregation of X-chromosomes at cleavage.	These develop due to influence of male hormone.

Question 7.
Down’s syndrome and Turner’s syndrome.
Answer:
Differences between Down’s syndrome and Turner’s syndrome are as follows

Down’s syndrome	Turner’s syndrome
It occurs due to the presence of an additional copy of the chromosome number 21. This condition is called trisomy of 21 chromosome.	It is a disorder caused due to the absence of one of the X-chromosome, i.e. 45 with XO.
It is an autosomal genetic disorder.	It is a sex-linked chromosomal genetic disorder.

Long Answer Type Questions

Question 1.
Discuss the chromosomal theory of sex-determination.
Answer:
Chromosomal Mechanism of Sex-Determination:
The male and female individuals normally differ in their chromosomal constituents. There are two types of chromosomes, i.e.

• Sex chromosomes or Allosomes The chromosomes responsible for sex determination, e.g. X and Y-chromosomes.
• Autosomes The chromosomes which determines the somatic characters.

X-chromosome was first discovered by Henking (1891). He named this structure as X-body. Scientists further explained that X-body was a chromosome and called it as X-chromosome. The concept of autosomes and allosomes was proposed by Wilson and Stevens (1902-1905) in chromosomal theory of sex-determination.
There are various types of chromosomal sex-determination mechanism observed in different animals as follows

Sex Differentiation:
Sex-determination in lower grade animals can be explained successfully by the genic balance and chromosomal theory. However, this is not the case with vertebrates and in some invertebrates, where the embryo develops certain traits of opposite sex along with its own. This indicates that sex of an organism changes under specific conditions. This may happen as a result of hormones secreted from the gonads of such organisms.
Some examples of sex differentiation are given below

Sex Reversal:
Artificial removal of gonads of either sex before puberty (castration or ovariectomy) results in the development of secondary sexual characters of the opposite sex. It is observed in fishes, amphibians, birds and some mammals, including humans. ,

In the given figure, the hen develops male secondary sex characteristics after the removal of ovaries. Thus, the bird is still female genotypically but phenotypically it becomes male.

Freemartin:
It is an infertile female mammal with masculinised behaviour and non-functioning ovaries. Freemartinism is the normal outcome of mixed sex twins in all cattle species, i.e. it occurs when the twins of opposite sex are born: also occurs occasionally in other mammals including sheep, goats and pigs.

In most cattle twins, the blood vessels in the chorions become interconnected, creating a shared circulation for both twins. Mostly the male hormones are produced first. If both foetuses are of the same sex this is of no significance, but if they are of different sex, male hormones pass from the male twin to the female twin.
The male hormones then masculinise the female twin and the result is a freemartin or sterile masculine female.

Question 2.
What is genic balance theory and explain its role in sex-determination?
Answer:
Genic Balance Mechanism:
The investigations on Drosophila by C. Bridges showed that female determiners were located on the X-chromosomes and that of male were on the autosomes. Hence, autosomes also plays an important role in determining sex in Drosophila melanogaster. Genic balance’ theory by Bridges proposed the sex-determination mechanism based on the ration of number of X-chromosomes (X) and sets of autosomes (A).

The table given below describes about the phenotypic sex of ‘ D. melanogaster based on X/A values

Gynandromorph in Drosophila as a Proof of Chromosomal Mechanism of Sex-Determination
Abnormal chromosomal behaviour in insects can result in the formation of gynandromorphs or sexual mosaics in which some parts of the animal exhibit female characters and other parts exhibit male characters.

Some gynandromorphs in Drosophila are bilateral intersexes with male colour pattern, body shape, and sex comb on one half of the body and female characteristics on the other half.

The failure of segregation (non-disjunction) of X-chromosomes at cleavage leads to formation of gynandromorphs. The chromosome complement of zygote is 2A + 2X. During first cleavage, one of the X-chromosomes is lost in one of the blastomeres.

As a result, one of the blastomeres acquires 2A + 2X complement which forms the female half while the other blastomere with 2A + X complement forms the male half. Thus, half of the body is female while the other half is male.

Question 3.
Explain sex-linked inheritance. Discuss the phenomenon with the example of colour blindness.
Answer:
Sex-Linked Inheritance:
Sex chromosomes contain genes primarily concerned with the determination the sex of the organism. In addition to sex genes, they also contain the genes to control other body characters, thus are called sex-linked genes. The somatic characters whose genes are located on sex chromosomes are known as sex-linked characters. The inheritance of a trait (phenotype) that is determined by a gene located on one of the sex chromosome is called sex-linked inheritance.

Sex-Linked Genes:
The sex-linked genes are of the following types
1. X-linked Genes These are sex-linked genes which lie on X-chromosomes, e.g. genes for colour blindness and haemophilia. These X-linked traits have a unique mode of inheritance as females have two doses of X-linked genes, while males have only one. Thus, males are hemizygous for X-linked traits they possess only half the number of X-chromosomes a female possess. An X-linked gene can be dominant or recessive due to which a female can be a heterozygous carrier of X-linked trait.

2. Y-linked Genes These are sex-linked genes, which are inherited straight from father to son or male to male, e.g. genes for hypertrichosis. Any gene which occurs exclusively on Y-chromosome is said to be holandric and it shows holandric inheritance pattern,

3. Pseudoautosomal Genes Genes located on homologous parts of both X and Y-chromosomes.

Inheritance of Sex-linked Characters:
The alleles for sex-linked traits are recessive to their normal alleles. These alleles express themselves in males, i.e. in heterogametic condition whereas in females, they express themselves only in homozygous condition (X^CX^C). In case the female is heterozygous for sex-linked gene (X^CX), the trait is not expressed in F₁-generation, but the female becomes carrier of the allele.

The X-chromosomes of carrier female is distributed equally to her children, while through male, it is distributed in daughters (in F₁-generation). The daughter then distributes her X-chromosomes equally to her children during F₂-generation (son or daughter). Thus, the X-chromosome does not pass directly from father to son but follows a criss-cross inheritance.

In other words, a male transmits his (X-linked) traits to his grandson through her daughter whereas, a female passes her traits to grand-daughter through her son. This pattern of inheritance where a trait skips a generation or criss-crosses the F₁-generation while passing the trait to F₂ is known as criss-cross inheritance.

Inheritance of Haemophilia
It is a sex-linked recessive disease, which is transmitted from an unaffected carrier female to some of the male offsprings. Due to this, patient continues to bleed even during a minor injury because of defective blood coagulation and hence, it is also called as bleeders disease. The gene for haemophilia is located on X-chromosome and it is recessive to its normal allele. In this disease, a single protein that is part of cascade of proteins involved in blood clotting is affected.

The possibility of a female becoming a haemophilic is extremely rare because mother of such a female has to be atleast carrier and father should be haemophilic, e.g. females suffer from this disease only in homozygous condition, i.e. X^CX^C. The haemophilic alleles shows criss-cross inheritance and they follow Mendelian pattern of inheritance. The family pedigree of Queen Victoria (who was a carrier of haemophilia) shows a number of haemophilic individual.

The inheritance is explained below


Four crosses explaining the inheritance of haemophilia allele in human, (a) Normal mother and haemophilic father, (b) Haemophilic mother and normal father, (c) Carrier mother and normal father and (d) Carrier mother and haemophilic father

Inheritance of Red-Green Colour Blindness:
It is a sex-linked recessive disorder, which results in defect in either red or green cone of eye. It does not mean the incapability to see any colour at all, infact it leads to the failure in discrimination between red and green colour. The gene for colour blindness is present on X-chromosome.

It is present mostly in males (X^CY) because of the presence of only one X-chromosome as compared to two chromosomes in females. A heterozygous female has normal vision, but is a carrier and passes on the disorder to some of her sons. Its inheritance pattern is similar to that of haemophilia.

Question 4.
Give an account of sex linkage in Drosophila and man.
Ans.
Sex linkage is the phenotypic expression of an allele related to the allosome of the individual. In autosomal chromosomes both sexes have the same probability of existing but since humans have many more genes on the female X-chromosome than on the male Y-chromosome, these are much more common than Y-linked traits. Examples of sex-linked traits in humans are haemophilia and colour blindness (for detail refer to text on page no. 147-148).

Thomas Hunt Morgan discovered sex linkage in fruitfly. It supported the chromosomal theory of heredity.
Morgan proposed that the inheritance of eye colour is related to the sex of the offspring. He found that the gene for eye colour is located on X-chromosome. There is no corresponding allele for this trait on Y-chromosome.

Example During the cross between white-eyed male and red-eyed female, the F₁-flies (both male and female) were all red-eyed indicating that white eye colour is recessive to the normal red eye colour.

A cross between red-eyed female and white-eyed male showing sex-linked inheritance in Drosophila

Odisha State Board CHSE Odisha Class 12 Biology Solutions Chapter 4 Reproductive Health Textbook Questions and Answers.

CHSE Odisha 12th Class Biology Chapter 4 Question Answer Reproductive Health

Reproductive Health Class 12 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Multiple choice questions

Question 1.
The experimental plant material used by Mendel was
(a) cowpea
(b) garden pea
(c) wild pea
(d) sweet pea
Answer:
(b) garden pea

Question 2.
Which of the following characters is not among the seven characters considered by Mendel for his hybridisation experiments?
(a) Seed colour
(b) Pod shape
(c) Flower position
(d) Flower shape
Answer:
(d) Flower shape

Question 3.
Which law Mendel would not have proposed, if the phenomenon of linkage was known to him?
(a) Law of unit character
(b) Law of dominance
(c) Law of segregation
(d) Law of independent assortment
Answer:
(d) Law of independent assortment

Question 4.
The number of genotypes produced in F2-generation in Mendel’s monohybrid cross was
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(c) 3

Question 5.
In which of the crosses, half of the offsprings show dominant phenotype?
(a) Tt × Tt
(b) TT × tt
(c) Tt × tt
(d) TT × TT
Answer:
(c) Tt × tt

Question 6.
Two allelic genes are located on the
(a) same chromosome
(b) two homologous chromosomes
(c) two non-homologous chromosomes
(d) any two different chromosomes
Answer:
(b) two homologous chromosomes

Question 7.
Red (RR) Antirrhinum is crossed with white (rr) one. The F₁-hybrid is pink. This is an example of
(a) complete dominance
(b) codominance
(c) incomplete dominance
(d) complete recessive
Answer:
(c) incomplete dominance

Question 8.
In a dihybrid cross in F₂-generation, the parental types are far greater in number than the recombinants. This is due to
(a) linkage
(b) incomplete dominance
(c) multiple allelism
(d) complete dominance
Answer:
(a) linkage

Express in one or two word(s)

1. A pair of Mendelian factors (genes) that appear at a particular location on a particular chromosome and control the same characteristic.
Answer:
Alleles

2. Phenomenon where in the heterozygous condition an intermediate phenotype is observed.
Answer:
Incomplete dominance

3. The phenomenon of a single gene contributing to multiple phenotypic traits.
Answer:
Pleiotropy .

4. Genes which move together and do not show independent assortment.
Answer:
Linked gene

5. A cross between the F₁-hybrids with any one of the homozygous parents.
Answer:
Back cross

Correct the sentences, if required, by changing the underlined word (s) only

1. The process of transmission of characters through generations is known as variation.
Answer:
inheritance

2. In Mendel’s monohybrid cross, the dwarf phenotype is always homozygous.
Answer:
Correct statement

3. In Mendel’s dihybrid cross in F₂-generation, nine phenotypes are produced.
Answer:
four

4. The phenomenon of linkage disproved the principle of independent assortment.
Answer:
Correct statement

5. In a test cross, always dominant parent is used.
Answer:
recessive

6. The distance between genes in a constructed gene map is expressed as Mendel unit.
Answer:
Morgan

Fill in the blanks

1. Monohybrid cross in Regeneration yields ____ number of phenotypes.
Answer:
two

2. Monohybrid cross in Regeneration yields ____ number of genotypes.
Answer:
three

3. The name of scientist often coined with linkage is ____ .
Answer:
TH Morgan

4. Genotype of a plant showing the dominant phenotype can be determined by ____ cross.
Answer:
test

5. In a cross between AaBB and aaBB, the genotypic ratio in Ft-generation will be ____ .
Answer:
1 : 1

Short Answer Type Questions

Write notes on the following

Question 1.
Law of independent assortment
Answer:
It states that when two pairs of traits are combined in a hybrid, segregation of one pair of traits is independent to the other pair of traits. As in the dihybrid cross of Mendel the presence of new combinations, i.e. round-green and wrinkled-yellow suggests that the genes for shape of seed and colour of seed are assorted independently. The results (9:3:3:1), indicate that yellow and green seeds appear in the ratio of 9+3 : 3+1 = 3:1.
Similarly, the round and wrinkled seeds appear in the ratio of9 + 3:3+1 = 3:1.

This indicates that each of the two pairs of alternative characters viz yellow-green cotyledon colour is inherited independent of the round-wrinkled characters of the cotyledons. It means that at the time of gamete formation the factor for yellow colour enters the gametes ” independent of R or r, i.e. gene Y can be passed on to the gametes either with gene R or r.

Question 2.
Multiple alleles
Answer:
Multiple allelism and Inheritance of Blood Groups:
Each gene has alternative forms or allelomorphs. For example, the genes for rail and dwarf characters of pea plant arc ailcics or allelomorphs. Here, former is called normal or wild type and Iatcr as mutant type.
Sometimes, there may no be any aiternative form such mutation that results in complete elimination of a gene is known as null mutation. Sometimes silent mutation occurs in which mutation does not have any effect of all.

These mutations occur in wild gene in any direction with a possibility of formation of many alternative alleles. Some genes may occur in more than two allelic forms, i.e. a gene can mutate several times to produce several alternative expressions such genes are called multiple alleles.

Question 3.
Chromosomal basis of inheritance
Answer:
It was proposed independently by Walter Sutton and Theodore Boyen in 1902. They united the knowledge of chromosomal segregation with Mendelian principles and called it chromosornal theory of inheritance.
According to this theory

• All hereditary characters must be with sperms and egg cells as they provide bridge from one generation to the other.
• The hereditary factors must be carried by the nuclear material.
• Chromosomes are also found in pairs like the Mendelian alleles.
• The two alleles of a gene pair are located on homologous sites on the homologous chromosomes.

Question 4.
Codominance
Answer:
Codominance:
It is the phenomenon in which two alleles express themselves independently when present together in an organism. In other words, it is the phenomenon in which offspring shows resemblance to both the parents,
e.g. ABO blood grouping in humans.

Question 5.
Incomplete dominance
Answer:
Incomplete Dominance:
It is a phenomenon in which phenotype of the F₁-hybrid offsprings does not resemble any of the parent, but is an intermediate between the expression of two alleles in their homozygous state. Carl Correns was the one who reported incomplete dominance in plant Mirabilis jalapa. He showed the petal colour inheritance in this plant. Here, the phenotypic ratio deviates from Mendel’s monohybrid ratio but the parental characters reappear in F₂-generation.

Question 6.
Law of segregation
Answer:
This principle states that, though the parents contain two alleles during gamete formation, the factors or alleles of a pair segregate from each other, such that a gamete receives only one of the two factors. Hence, the alleles do not show any blending and both the characters are recovered as such in the F₂-generation though one of these is not seen in the F₁-generation.

Question 7.
Linkage
Answer:
The genes of a particular chromosome show the tendency to inherit together. This phenomenon of genic inheritance in which genes of a particular chromosome show their tendency to inherit together, i.e tendency to retain their parental combination even in the offsprings is known as linkage.

Question 8.
Recombination
Answer:
They attributed this due to physical association of the two genes and coined the term ‘linkage’ to describe this physical association of genes on a chromosome and the term ‘recombination’ to describe the generation of non-parental gene combinations. Morgan performed a test cross by crossing heterozygous grey-bodied and long-winged with homozygous recessive black-bodied and vestigial-winged fly

Question 9.
Test cross
Answer:
A special back cross to the recessive parent is known as test cross. This method was devised by Mendel to determine whether the dominant phenotype is homozygous or heterozygous.

For example, in a monohybrid cross between violet colour flower (W) and white colour flower (w), the F₁-hybrid was a violet colour flower. If all the F₁-progenies are of violet colour, then the dominant flower is homozygous and if the progenies are in 1:1 ratio, then the dominant flower is heterozygous.

Question 10.
Back cross
Answer:
Back cross is a cross of F₁ -progeny back to one of their parents. In back cross, there can be two possibilities, i.e. F₁ -hybrid to be crossed with homozygous dominant parent or with homozygous recessive parent.

Differentiate between the following

Question 1.
Homozygous and Heterozygous
Answer:
Differences between homozygous and heterozygous are as follows

Homozygous	Heterozygous
It is a condition when both alleles of a gene are similar.	It is a condition when both alleles of a gene are dissimilar.
The genotype is expressed as TT or tt.	The genotype expressed as Tt.
They are true breeding to purelines.	They are not true breeding.
The gametes produced by them are similar in genotype.	The gametes produced by them are of two types, one with dominant allele and other with recessive allele.

Question 2.
Genotype and Phenotype.
Differences between phenotype and genotype are as follows
Answer:

Phenotype	Genotype
It refers to observable traits or characters.	It refers to the genetic constitution of an individual.
It results from expression of genes.	It constitutes single gene pair or sum total of all the genes.
The phenotypic ratio of Mendel’s monohybrid cross is 3 : 1.	The genotypic ratio of Mendel’s monohybrid cross is 1:2:1.
It may change with age and environment.	It remains the same throughout the life of an individual.

Question 3.
Dominant genes and Recessive genes.
Answer:
Differences between dominant genes and recessive genes are as follows

Dominant genes	Recessive genes
When an allele expresses itself in the presence of its recessive allele, it is called dominant trait.	It can only express in the absence of its dominant allele and remain masked in its presence.
Dominant allele forms a complete functional enzyme due to which complete polyeptide is formed to express.	Recessive allele forms incomplete polypeptide enzyme due to which non-functionai polypetide is formed and fails to express completely.

Question 4.
Back cross and Test cross.
Answer:
Differences between back cross and test cross are as follows

Back cross	Test cross
It is a cross involving F1-progeny and either of the parents.	It is a cross involving
It is used by scientists to improve a breed or variety of plant or animal.	F1-individual and its recessive parent.

Question 5.
Qualitative inheritance and Quantitative inheritance.
Answer:
Differences between qualitative inheritance and quantitative inheritance are as follows

Qualitative inheritance	Quantitative inheritance
It deals with the inheritance of qualitative characters.	It deals with the inheritance of quantitative characters.
Each character is controlled by one pair of contrasting alleles.	Each character is controlled by more than one pair of non-allelic genes (Polygenes).
Each character has two distinct expressions, i.e. exhibits two distinct phenotypes.	Each character has an intergrading range of phenotypes.
The degree of expression remains the same whether the character is controlled by one or both the dominant genes.	The degree of expression depends on the number of the dominant genes.
Phenotypic expression is not affected by the environment.	Phenotypic expression is influenced by environmental factors.
Monogenic inheritance exhibits discontinuous pattern of inheritance.	Polygenic inheritance represents continuous pattern of inheritance.
F1-individuals resemble the dominant parent.	F1-individuals exhibit intermediate expression between the two parents.
F2-individuals exhibit 3:1 ratio. Intermediate expressions are not found.	In F2-generation, individuals with intermediate genotype and phenotype are maximum.
Examples of monogenic or qualitative inheritance are yellow or green coat color or round or wrinkled seed character in pea seeds.	Examples of polygenic or quantitative inheritance are height, weight, intelligence and skin color in human beings, milk yield in cattle and egg production in poultry.

Long Answer Type Questions

Question 1.
Give an account of Mendel’s monohybrid cross. What inference did Mendel draw from this experiment?
Answer:
Monohybrid Cross
The study of inheritance of a single pair of alleles or factors of a trait at a time (monohybrid cross) is called one gene inheritance. When a cross is made between pure tall and pure dwarf plant (for purity, the pureline is taken into consideration) in F₁-generation, all plants will be tall.

When F₁ -plants are self-pollinated, then in F₂-generation both tall and dwarf plants are found in approximate ratio of 3 : 1.

The dwarf plants of F₂ on self-pollination, produce dwarf plants generation after generation, while among tall plants, only 1 /3rd show this character generation after generation (pureline) and rest 2/3rd produce tall and dwarf in 3 : 1 ratio again (F₃ -generation).

Explanation Mendel’s monohybrid cross explained that in each main pair of alternative character one is expressed and other is masked.
The character which is expressed in F₁-generation is called dominant and the one which is not expressed is called recessive.

The monohybrid cross between tail and dwarf

In F₂-generation, the genotypic ratio is 1 : 2 : 1 and phenotypic ratio is 3 : 1. Mendel came to the conclusion that progeny possessing similar factors is called homozygous and the one which is hybrid is called heterozygous.

Mendel used english letters to record his observations of breeding experiments. He assigned capital letters for dominant characters and small letters for recessive characters which tabulated in the given below table

Characters	Dominant	Recessive
Seed shape	Round (R)	Wrinkled (r)
Seed colour	Yellow (Y)	Green (y)
Pod shape	Full (F)	Constricted (f)
Pod colour	Green (G)	Yellow (g)
Flower/Pod position	Axial (A)	Terminal (a)
Seed coat colour/Flower colour	Red/Violet (R/V)	White (r/v)
Plant height	Tall (T)	Dwarf (t)

Based on his observations on monohybrid crosses, Mendel proposed two general rules in order to consolidate his understanding of inheritance in monohybrid crosses.

Based on the Mendel’s observations, the German scientist Carl Correns formulated certain principles of heredity. These now known as Mendel’s laws of inheritance or the principles or laws of inheritance.
These are
Principle of Dominance:
It states that when two contrasting alleles for a character come together in an organism, only one is expressed completely and shows visible effect. This allele is called dominant and the other allele of the pair which does not express and remains hidden is called recessive.

For example, in the monohybrid cross when dwarf plant is crossed with tall plant, the Frgeneration are all tall plants. This shows that allele for tallness is dominant.

Question 2.
State and explain Mendel’s laws of inheritance.
Answer:
Following inferences were made by Mendel based on his observations
1. He proposed that some ‘factors’ passed down from parent to offsprings through the gametes over successive generations. Now-a-days, these factors are known as genes. Genes are hence, the units of inheritance. Genes which code for a pair of contrasting traits are known as alleles or allelomorphs, i.e. they are slightly different forms of the same gene.

2. Genes occur in pairs in which, one dominates the other called as the dominant factor or the gene which expresses itself, while the other remains hidden and is called recessive factor.

3. Allele can be similar in case of homozygous (TT or tt) and dissimilar in case of heterozygous (Tt).

4. In a true-breeding tall or dwarf pea variety, the allelic pair of genes for height are identical or homozygous.

5. TT and tt are called genotype (sum total of heredity or genetic make up) of the plant, while the term tall and dwarf are the phenotype.

6. When tall and dwarf plants produce gametes by process of meiosis, the alleles of the parental pair segregate and only one of the alleles gets transmitted to a gamete. Thus, there is only 50% chance of a gamete containing either allele, as the segregation is a random process.

7. During fertilisation, the two alleles, ‘T’ from one parent and V from other parent are united to produce a zygote, that has one ‘T’ and one allele or the hybrids have Tt.

8. Since, these hybrids contain alleles which express contrasting traits, the plants are heterozygous.

Question 3.
What do you mean by back cross and test cross? Explain test cross through an example.
Answer:
Back cross is a cross of F₁ -progeny back to one of their parents. In back cross, there can be two possibilities, i.e. F₁ -hybrid to be crossed with homozygous dominant parent or with homozygous recessive parent.

A special back cross to the recessive parent is known as test cross. This method was devised by Mendel to determine whether the dominant phenotype is homozygous or heterozygous.

For example, in a monohybrid cross between violet colour flower (W) and white colour flower (w), the F₁-hybrid was a violet colour flower. If all the F₁-progenies are of violet colour, then the dominant flower is homozygous and if the progenies are in 1:1 ratio, then the dominant flower is heterozygous.

Question 4.
Describe Mendel’s dihybrid cross.
Answer:
When two or more than two characters are taken in a cross it is called as polyhybrid cross, e.g. dihybrid cross, trihybrid cross, etc. A dihybrid cross is a cross involving two pairs of contrasting characters. For example, when a cross is made between yellow-round and wrinkled green seeds (both pureline homozygous), plants with only yellow round seeds are seen in F₁-generation but in F₁-generation, four types of combinations are observed.

Two of these combinations are similar to the parental combinations and others are new combinations. These are round green and wrinkled yellow.
The cross can be seen as shown in the figure

Phenotypic Ratio Round yellow : Round green : Wrinkled yellow : Wrinkled green = 9 : 3 : 3 : 1
Genotypic Ratio 1 : 2 :2 : 4 : 1 : 2 : 1 : 2 : 1

The ratio of four combinations in F₂-generation comes out to be 9 (round, yellow) : 3 (round, green) : 3 (wrinkled, yellow) : 1 (wrinkled, green). This ratio is called phenotypic dihybrid ratio. Phenotypic ratio of dihybrid test cross is 1 : 1 : 1 : 1.

Mendel’s Postulate Based on Dihybrid Cross:
Based on the result obtained from dihybrid crosses or two gene interaction, Mendel proposed the fourth postulate, i.e. law of independent assortment.

Question 5.
Give an account of linkage and recombination.
Answer:
Linkage, Crossing Over and Recombination:
According to ‘chromosomal theory of inheritance’, the chromosomes are vehicles of inheritance. Hence, the number of genes per individual for exceed the number of chromosomal pairs, i.e. each chromosome bears many genes. These genes are arranged in linear fashion over the chromosome and cannot show independent assortment.

In other words, we can say that the genes of a particular chromosome show the tendency to inherit together. This phenomenon of genic inheritance in which genes of a particular chromosome show their tendency to inherit together, i.e tendency to retain their parental combination even in the offsprings is known as linkage.

Morgan and his group observed in Drosophila that when the two genes in a dihybrid cross were situated on the same chromosome, the proportion of parental gene combinations were much higher than the non-parental type.

They attributed this due to physical association of the two genes and coined the term ‘linkage’ to describe this physical association of genes on a chromosome and the term ‘recombination’ to describe the generation of non-parental gene combinations. Morgan performed a test cross by crossing heterozygous grey-bodied and long-winged with homozygous recessive black-bodied and vestigial-winged fly. They obtained the following results

Phenotype	Per cent of occurrence
Grey body long wing	41.5
Black body vestigial wing	41.5
Grey body vestigial wing	8.5
Black body long wing	8.5

This result was not in accordance with Mendel’s law of inheritance. Now suppose in order to explain, we assume the alphabets G and g for grey and black body colours and L and 1 for long and vestigial wings, respectively.

Thus, linkage is a phenomenon of genic inheritance in which genes of a particular chromosome show their tendency to inherit together.
Morgan and his group also found that even when genes were grouped on the same chromosome, some genes were tightly linked, i.e. linkage is stronger between two genes, if the frequency of recombination is low (cross-A). Whereas, the frequency of recombination is higher, if genes are loosely linked, i.e. linkage is weak between two genes (cross-B) as given in figure


Linkage : Results of two dihybrid crosses conducted by Morgan. Cross ‘A’ shows crossing between genes y and w ; Cross ‘B’ shows crossing between genes w and m. Here, dominant wild type alleles are represented with (+) sign in superscript

Those traits present on same chromosome, which do not show any production of recombinants are completely linked which is known as complete linkage and it is very rare.

Linkage Groups:
All the genes linked together in a single chromosome constitute a linkage group. The number of linkage group in an organism is equal to their haploid number of chromosomes. This hypothesis was proved by TH Morgan by his experiments on Drosophila.

Morgan and his group hybridised yellow-bodied and white-eyed females with brown-bodied and red-eyed males (wild type) and intercrossed their F₁-progeny (cross A). It was observed that the two genes did not segregate independently of each other and the F₂-ratios deviated significantly from 9:3:3 :1 ratio.

In F₂-generation, parental combinations were 98.7% and the recombinants were 1.3%. In another cross (cross-B), between white-bodied female fly with miniature wing and a male fly with yellow body and normal wing, parental combinations were 62.8% and recombinants were 37.2% in F₂-generation. Thus, it was proved from the crosses that the linkage between genes for yellow body and white eyes is stronger than the linkage between the white body and miniature wing.

Chromosome Maps or Linkage Maps:
Alfred Sturtevant (Morgan’s student) used the frequency of recombination between gene pairs on the same chromosome as a measure of the .distance between genes and ‘mapped’ their position on the chromosome. Genetic maps are now used as a starting point in the sequencing of whole genomes as done in case of human genome sequencing project.

The frequency of recombination Cross Over Value (COV) is calculated by using the formula

A linkage or genetic chromosome map is a linear graphic representation of the sequence and relative distances of the various genes present in a chromosome. 1% crossing over between two linked genes is known as 1 map unit or Morgan (after TH Morgan, who is considered as ‘Father of Experimental Genetics’).

Odisha State Board CHSE Odisha Class 12 Economics Solutions Chapter 13 Public Finance Questions and Answers.

CHSE Odisha 12th Class Economics Chapter 13 Question Answer Public Finance

Group – A

Short type Questions with Answers
Answer with in Two/Three sentence.

Question 1.
What is Public finance?
Answer:
Public finance studies the income, expenditure of the government & its rational adjustment with each other for the purpose of economic progress. It also includes the revenue & capital expenditures of the government & sources of revenue to be collected.

Question 2.
Balanced budget is the best budget
Answer:
In case of balanced budget, the government receipt becomes equal to government expenditure. Here, there is no surplus nor any deficit in respect of govt, expenditure or income & so it is treated as the best budget.

Question 3.
Deficit budget is beneficial to the UDCs
Answer:
In deficit budget the govt, expenditure is more than the govt, receipts. There is ample scope for developmental activities. Hence it is beneficial to the UDCs.

Question 4.
What is Surplus budget?
Answer:
Surplus budget is one type of unbalanced budget in which revenue receipts for the budget period are greater than the expenditure to be incurred. Hence, the total revenue earned through various sources of the Government has not been exhausted and some amount of income remains unspent or unutilised.

Question 5.
Write down two demerits of Deficit budget.
Answer:
Deficit budget is prone to inflation. If it is not properly managed, there will be wide gap between demand and supply, Inflation will come up. Deficit budget creates inflation. So, price of the goods to be exported increases. The volume of export comes down. It will reduce the amount of foreign currency in the country.

II. Answer within Five/Six sentence :

(A) write shot notes on :
1. Public Finance:
Answer:
Public finance deals with the income and expenditure of public authorities and with the adjustment of one to another.” Obviously, public finance also deals with the problems of adjustments of income and expenditure of the Government. The methods of expenditure of public bodies and income of public bodies as well as borrowing by public bodies are known as operations of public finance. According to Bastable “Public finance deals with expenditure and income of public authorities of the State and their mutual relation as also with the financial administration and control”. Thus public finance was concerned with the explanation of revenue and expenditure process of the public authorities.

2. Budget:
Answer:
Budget is a financial statement of income and expenditure of public authorities. It is a reflection of not only taxation and public expenditure policy, but also of a plan for future course of action. It is designed to Secure the normative ideas of allocation, distribution, stabilisations and growth. Budget, thus refers to the financial arrangement covering the income and expenditure of the Government especially for a particular year. It is an aimual plan of income and expenditure of the public authorities which reflects the economic activities to be undertaken by the Government for a particular year.

3. Balanced budget:
Answer:
Budget is viewed as a balanced budget if the Government revenues are equal to Government expenditures. In such budget, there exists no gap between the total income and total expenditure of the Government during a particular time-period. This sort of budget is appreciated for underdeveloped countries which suffer from chronic destability due to considerable amount of deficit. Besides, this budget avoids extravagant expenditure and thus ensures effective allocation and mobilisation of the available resources.

4. Deficit Budget:
Answer:
Deficit budget is that budget in which the government expenditure exceeds government revenue. In this case government receipts for the budget period is inadequate to meet the government expenditure. The gap between the government receipt & government expenditure is met through public debt & issue of new currency notes, Deficit budget is expansionary in nature. Deficit budget controls unemployment, deflation etc.

5. Surplus budget:
Answer:
The surplus budget is that in which anticipated revenue of the government is more than the anticipated expenditure. In this budget, revenue receipts during budget period are greater than the cost payments. The outcome of surplus budget is very discouraging in modem world. It has got contractionary effect. Besides, it checks unproductive expenditure & reduces debt burden. This budget is not favourable for developing countries.

(B) Distinguish Between
6. Public finance & Private finance:

1. Public finance deals with the income & expenditure of the public authorities i.e. local, state & central government. But the private finance deals with the income & expenditure of the private individual.
2. Public finance aims at collective welfare of the society whereas private finance aims at individual welfare.
3. In public finance, government adjusts its income to its expenditure whereas in private finance, the individual adjusts its expenditures to its income.
4. In public finance, the government can not avoid or postpone its expenditure whereas in private finance, it can be avoided or postponed.

Group – B

Long Type Questions With Answers

Question 1.
What is public finance ? Compare & contrast between Private finance & Public finance.
Answer:
The two terms ‘public’ & ‘finance’ denotes income & income expenditure of the government. Here public implies government which collectively considers the people of the State. Similarly, finance refers to income & expenditure, public finance denotes income & expenditure of the government. According to H. Dalton, public finance is a “subject which is concerned with the income & expenditures of public authorities & with the adjustment of the one with the other”. In simple way, public finance deals with the income of the public authorities (government) i.e. local, state or central. It was a practice among the writers on public finance to compare public with private finance. Such a comparison will enable us to have a clearer picture of the public finance.

(1) It is said that an individual will adjust his expenditure to his income. On the other hand, it is pointed out that the state will adjust its income to expenditure. In the case of the individual, income determines the expenditure. In the case of the state, expenditure determines its income. Ofcourse, this statement has its exception. An individual too tries to increase his income when it is not enough to meet his essential expenditure. On the other hand, the state too curtails its expenditure when it is not possible to raise its income. After all, the sources of income to the state also are not completely elastic.

(2) Both the individual and state attempt to equalise income and expenditure. Both of them try to earn more or at least borrow to meet the additional expenditure but there is one difference. An individual can borrow from another individual or institution, i.e., externally. A state can borrow externally from foreign citizens, institutions or government as well as internally from its own citizens. Further, the government may also inflate, i.e., print more notes to meet its expenditure, This course is entirely out of reach for the individual.

(3) Generally, the state adopts a year as its accounting period and attempts to equalize revenue and expenditure during that period. An individual does not have any such-rigid scheme of balancing income and expenditure in every year. However even with regard to a state. There is no particular sanctity attached to a year. The budget period may will be changed to three or four years.

(4) An individual is supposed to distribute the expenditure among various items so as. to equalize their marginal utilities. In case of the state, this is not considered to be possible since it isnot a person. But even in the case of the state, the statesmen should so distribute the expenditure that marginal utilities to the community on all forms of expenditure must be the same. Ofcourse, neither the individual nor the public authorities will be able to do these calculations very accurately. There can at best, be only an approximately correct distribution following this principle.

(5) The government will be in a much better position to make deliberate changes in its income and expenditure than an individual. An individual has limited resources. The government can similarly change the pattern of expenditure with greater than the individual.

(6) The government spends on certaqin ojects like security, peace and order, national defence etc. These are entirely beyond the scope of private finance.

(7) the individuals can afford to discont future at a higher rate. But the state cann’t do so since it will be in perpetual existence. It has to provide for the future. It has to compensate for the deficiency in the individual’s provision for future.

(8) In private business, ‘special service and special payment’ is the principle. But in the case of the state here is usually no relationship between the service rendered by the state and the payment it demands from individuals.

(9) The individual will have an eye on quick returns and high profits while making investments, the state doesn’t follow this principle. It sometimes undertakes even follow this principle. It sometimes undertakes even singly, unproductive projects which are beneficial to the society in the long run.

(10) The effects of expenditure on the part of the state are different from the effects of expenditures by individuals. Ofcourse the effect of expenditure in creating effective demand for goods is the same in regard to both. However, the variation of the public expenditure has become an important means of anti cyclical policy because of its greater administrative convenience.

(11) In Private business, cost of production can be compared to the price of the product. But in case of the state, it is rather difficult to compare the cost of the service with the value of the service. Both cost and value can n’t be easily estimated in all cases. Defence service provides an example for this.

(12) Generally the financial operations of the individual are keep secret. They will not be open for public qaze. But the financial operations of the state are always public. They have to be approved before hand by the appropriate authority like the parliament. The people have a right to scrutinize the expenditure since they meet the bills through paying taxes.

(13) An individual can ebcome bankrupt when his assets are short of his liabilities. But there is ordinarily, no question of a state going bankrupt. The>liabilities of the state can be as certained, but its assets can’t be so precisely ascertained because they are just the pme as the assets of all the citizen together.

Question 2.
What is budget ? Discuss various types of budget.
Answer:
Budget is a financial statement of income and expenditure of public authorities. It is a reflection of not only taxation and public expenditure policy, but also of a plan for future course of action. It is designed to secure the normative ideas of allocation, distribution, stabilisations and growth. Budget, thus refers to the financial arrangement covering the income and expenditure of the Government especially for a particular year. It is an annual plan of income and expenditure of the public authorities which reflects the economic activities to be undertaken by the Government for a particular year.

Purpose : The purpose of a Government budget is varied. There are a number of objectives which the budget seeks to attain simultaneously. The overall purpose is to use the budget as an instrument of economic policy. A budget is such a plan which explicitly mentions the programmes that are to be taken up in the course of the fiscal year. Secondly, different programmes may need different durations for completion. What part of the action can be completed within a fiscal needs to be specified so that implementing agency clearly can know as to which portion of the programme should be completed within a specific year.

Thus budget spells out such year wise responsibility. Thirdly, the implementation of a programme requires availability of necessary funds. The extent of availability depends upon the budgetary sources of revenue. Hence, the programme structure has to be built which can be supported by funds. The budget draws up schemes of revenue mobilisation on the one hand and programmes of the public expenditure on the other. Fourthly, to achieve efficiency in revenue collection, the expenditure on the accounts of the collectorate is specified on the basis of the past trend, present level of cost of collection in the budget. F ifthly, to achieve efficiency in public expenditure physical targets of attainment are specified in the budget.

Sixthly, formulation of future programmes on the basis of past experience is an important purpose of the Government budget. Seventhly, an important purpose of the budget is to allow the legislature and the people to appreciate the overall programme framed in it in the back drop of prevailing economic situations. This is why a good budget is accompanied by an analytical account prevailing economic situation and financial position. Eighthly, investment, consumption and capital formation to assess the trend of growth in the economy. Ninthly, the main purpose of the budget in developed countries is to act as an analytical fiscal weapon. This is done through the manipulation of the budget balance. Lastly, the budget serves the purpose of public accountability of funds to a considerable extent.

Types of budget: As a suitable fiscal device, the budget may be classified into two categories like balanced budget and unbalanced budget. This classification of the budget is made on the basis of the difference between the total revenue (income) and total expenditure of the Government.

Balanced budget: Budget is viewed as a balanced budget if the Government revenues are equal to Government expenditures. In such budget, there exists no gap between the total income and total expenditure of the Government during a particular time-period. This sort of budget is appreciated for underdeveloped countries which suffer from chronic destability due to considerable amount of deficit. Besides, this budget avoids extravagant expenditure and thus ensures effective allocation and mobilisation of the available resources. In spite of these merits, this type of budget is not conductive to economic development which requires huge funds.

Surplus budget: Surplus budget is one type of unbalanced budget in which revenue receipts for the budget period are greater than the expenditure to be incurred. Hence, the total revenue earned through various sources of the Government has not been exhausted and some amount of income remains unspent or unutilised. This budget, though checks extravagant expenditure, is not suitable for economic development It is because the amount earned is not totally utilised. If this budget is adopted economic prosperity cannot be expected. But this budget is a cure during the period of inflation.

Deficit budget: Deficit budget is one in which revenue receipts for the budget period arc less than the expenditures required for.. In this budget, the income Of the Government becomes inadequate to meet expected expenditure. Scope for economic development. Secondly, this budget is a cure during the period of depression. But this budget is found to be inflationary if the deficit becomes, excessive. However this budget has got its overall importance as it results in economic prosperity.

In the advanced countries, a balanced budget is pursued at a time when the economy suffers neither from inflation nor from unemployment or depression so that objective of maintaining full employment with price-stability is achieved. When the economy suffers from inflation, a surplus budget is operated while a deficit budget is purchased when the economy suffers from unemployment. The developing and underdeveloped countries normally suffer from idle resources and to make their proper use, additional expenditures are incurred and hence, they mostly pursue deficit budgets.

Question 3.
Budget in an instrument of economic policy. Justify.
Answer:
Government budget is an important instrument of economic policy in both developed and developing countries. In the developed countries, the economy operates at full employment level and hence, there does not exist unemployed resources. But the economy is subject to trade cycle and therefore, occasionally faces the problems of depression of unemployment and inflation or pressure of excess purchasing power. In the underdeveloped countries, the economy operates at less than full empolyment level and hence, the main problem is how to attain economic growth. In these poor countries, growth process is faced with a number of problems. They are allocational, distributional and stabilisational. Budget serves as an important device to achieve economic development is these countries also. The following are the important ways in which the Government budget can influence the economy of a country.

(i) Revenue raising device : The Government requires enough revenue to discharge its fiscal responsibility. Modem countries have increasingly become welfare states with larger and larger State activities coming under the fold of public sector. Hence, resources have to be found in sufficient quantity. Budget secures this purpose through a financial plan. The receipts side of the budget clearly mentions the sources and the extent of funds for the purpose of financing state activities.

(ii) Incentive to economic activity: Budgetary receipts as well as expenditures ca eatly influence economic activities both in the industrial and agricultural sectors. Through tax concessions and discriminatory taxes, the budget can influence production and productivity in favour of these secto; s which the Government likes to promote. Important industries in the priority list of Government may be granted tax holiday or tax concessions in order to attract promising extrepreneurs to these ventures. Similarly, agricultural activity and production can be increased through budgetary provisions of free or subsidised supply of agricultural inputs and extension services.

(iii) Human capital formation : The most important need for a country’s economic development is human capital formation. The level of human capital formation like education, medical and public health, etc. is very poor in the underdeveloped countries. Unless people are educated and healthy, they cannot be good workers and their productivity cannot be increased. Budgetary provisions can serve this purpose. Since investment on such human capital formation is heavy and subjected to long gestation period, funds will not come from private sector. It is only the Government which can rise the level of general and technical education and of health and productive capacity by providing educational and health facilities through budgetary outlays.

(iv) Building of economic overheads : The main reason of underdevelopment of the poor countries is absence of proper economic infrastructure. Without proper transport and communication training facilities for workers and entrepreneurs, industrial development is not possible. Similarly agricultural production and productivity cannot improve in the absence of proper irrigation facilities, flood control measures, technological improvements with research and development activities etc. These facilities must be provided by the Government. The cost of supplying these services is heavy and cannot be raised directly from the beneficiaries. Therefore, these facilities are supplied free of direct charges through budgetary provision. Thus budget has tremendous influence on the industrial and agricultural development.

(v) Diversion of resources to more useful production :Free market mechanism leads to production of those goods and which give maximum investment is generally concentrated on the production of luxury commodities. It is therefore, necessary to divert resources to the production of more useful goods and services, particularly of the kind of mass consumption ones. This can be done by Government interference thorough the budget. Imposition of heavy tax on harmful and less essential goods and tax exemption or tax concessions granted to more essential goods and services can divert resources to the production of right kind of goods and services. Grant of facilities through budgetary expenditure can also do the same job.

(vi) Proper allocation of resources : Most efficient allocation of resources is given by the equality between marginal cost and price which is possible only under perfect market conditions. Underdeveloped countries seriously suffer from mal-allocation of resources. The general market conditions in private sectors are set by existence of monopoly, monopolistic competition and oligopoly. To correct this mal-allocation, the Government has to interfere either in the form, of production subsidy or supply of goods and services by public authorities so that the gap between average revenue (price) and the marginal cost is reduced as far as possible. This is the reason why the heavy investment public welfare industries which are subjected to decreasing cost conditions are increasingly coming under the fold of public sector.

(vii) Balanced development: Underdevelopment countries suffer from regional imbalance in economic development. Left to the private sector which is motivated by profit maximisation, the industries will be located in the urban and already developed areas. The Government can correct this geographical imbalance by setting up public sector industries will be located in the urban and already developed areas. The Government can correct this geographical imbalance by setting up public sector industries in backward areas. Moreover, the development of agriculture and small scale and village industries can be secured through Government patronage in the terms of supply of infrastructure facilities and various incentives or subsidy measures. This will develop the econoniy of rural areas.

(viii) Income and employment: Since underdeveloped countries, are low income economies, people live in poverty and hence, saving and investment is very low. Income of the people can be increased only through increased productivity and production. Budgetary provisions can go a ’ ng way to achieve this. When agricultural technology is improved though budgetary programmes, the income of the people engaged in agriculture rises. People get gainful employment in the sector. Improvement in small scale industries inthe backward regions will increase employment opportunities in these industries. The budgetary provisions of employment-related tax concessions can influence creation of employment opportunity in the private sector also.

(ix) Saving and investment: In-underdeveloped countries the level of saving and investment is very low. Moreover without increased saving and investment, economic growth cannot be achieved. Due to low level of income, marginal propensity to consume is very high and hence, the mass people cannot save. Public saving is, therefore necessary. Taxation of various types serves this purpose. The saving and investment of private individuals are also influenced by the savings investment related tax concessions and other budgetary subsidy programmes. Capacity and wiHjngness to work, save and invest of the people is increased through various human capital formation measures and creation of employment opportunities. These are all done through budgetary expenditures.

(x) Poverty removal: Poverty removal programme is a part and parcel or the budget in underdeveloped countries. All expenditure measures are designed in such a way that they directly or indirectly influence reduction of poverty inthe economy. Thus when budgetary resources are spent on account of education, whether general or technical and vocational, or on health measures, land
reforms, flood control and irrigation, an important objective is to remove poverty of people. Direct budgetary programmers for poverty removal are those of increasing employment opportunities and creation of community assets like those under I.R.D.P., N.R.E.P. or R.L.E.GP. schemes as in India, employment insurance, social security, consumption subsidy, public distribution system and price support programmes, low-income housing, area development, input supply, agricultural wage restructuring etc.

Question 4.
What is balanced budget ? State its merits & demerits.
Answer:
A budget is said to be balanced whose anticipated revenue and expanditure are equal. In the opinion of Prof. Dalton, “A balanced budget is that over a period of time, revenue does not fall short of expenditure.

Balanced budget may be true in accounting sense. It is nothing but a balance sheet approach. But in practice it is not easy to have a balanced budget as it tends to be either surplus or deficit as per the necessity of time. Budget can be balanced only in average, by taking a number of years together. So, balanced budget for a particular year is often theoretical. However, attempts should be taken to maintain balance as far as possible.

Merits of Balanced budget: Balanced Budget was the brain child of the classical economists for its following merits.
(i) Checks Wasteful Expenditure : In case of balanced budget, the Government designs its public expenditure according to its revenue. To assure welfare to the community, expenditure is made through rational planning. There can not be reckless and unproductive public expenditure. So, financial discipline of the Government can be assured.

(ii) Economic Stability : In case of balanced budget, what Government collects from the people and what it spends are the same. So, as believed by the classical economists, national income does not change. It brings room for neither inflation nor deflation. Economy experiences every type of normalcy.

(iii) Controls over Public Debt: In balanced budget, anticipated income and expenditure are equal. So, as there is no excess expenditure, there is no scope for public debt.

(iv) Favourable for Developed Countries : Balanced budget is a boon for developed countries. The countries which are already in the apex of development only need to continue the existing rate of development with stability. It can very well be possible through balanced budget.

(v) Limited Role of Government: In modem times, in most of the countries, Government does not like to shoulder more responsibilities Most of the economic functions are left to the private hands. So, public budget tends to be smaller. It creates room for balanced budget. All these argue in favour of balanced budget.

Demerits of Balanced Budget:- However, balanced budget has got so many demerits. Those are noted below.
(i) Paper Cultivation : A public budget should aim at provision of the maximum welfare for the community. Otherwise, all the activities, involved in preparation of budget will go down the drain. It will only be mere paper cultivation. It happens in case of balanced budget.

(ii) Not Effective in Modern World : In classical economy, Say’s Law of Market is obeyed. It suggests for a normal situation as whatever supplied is automatically demanded. Equilibrium has to prevail everywhere. In support of this, balanced budget is advocated. But in the modem world, normalcy is a dream. There are a number of problems like unemployment, over production, under production, economic instability etc. To tackle these problems, balanced budget can not be the right solution.

(iii) Not Effective for Developing Countries : Every developing country like India requires higher productive public expenditure for optimum utilisation of available resources. It can not be possible if the country follows balanced budget as it suggests for the least public expenditure and the minimum Government involvement.

(iv) Wasteful Expenditure : In the opinion of Prof. Arthur Smithies, “It is quite possible that to have balanced budget during a period of time the Government may lead to wasteful public expenditure. ” Balanced budget suffers from inadequate finance. Some of the Government projects remain incomplete.

(v) Restricts Freedom of Public Authority : Modem state is welfare oriented. To provide welfare, it has to spend on various purposes which require Himalayan public expenditure. But, due to balanced budget, the Government does not have free hand to spend and to assure welfare. All these demerits of balanced budget suggest to follow unbalanced budget as an appropriate fiscal policy.

Question 5.
What is deficit budget ? Discuss its merits & demerits.
Answer:
In case of deficit budget, anticipated expenditure is higher than anticipated revenue. Prof. Taylor has rightly mentioned deficit budget as that whose revenue receipts for the bqdget period are less than the cost payments. Deficit budget is met by the Government through public debt, issue of new notes etc.

Deficit budget has expansionary effect. When more is spent for the people than what is taxed, the national income increases in multiple. It is helpful to control deflation and to bring economic stability. It provides free hand to the Government for all round development. So most of the developing countries are following this budgetary policy.

Merits of Deficit Budget: Deficit Budget has the following merits.
(i) Increases National Income : In case of deficit budget, Government’s expenditure is higher than its income. That means, people receive more than what they pay in term of tax. As a result national income increases in multiple. There is every scope for higher economic growth.

(ii) Controls Unemployment: When deficit budget increases national income in multiple, the effective demand goes up. It encourages higher investment and employment. Employment of the economy goes on inerteasing in multiple.

(iii) Controls deflation : Deficit budget has got the capacity to increase national income in multiple. So, deflation which refers to decrease in price due to low income can be cured.

(iv) Not inflationary : Inflation occurs due to higher demand than what is supplied. It can be effectively controlled if production can be simultaneously increased with increase in demand. In case of deficit budget Government enjoys free hand to spend in various productive purpose. It leads to higher increase in national production. It brings mild inflation which is favourable to the economy.

(v) Maximum Utilisation of Resources : Deficit budget creates scope for higher productive expenditure. The available resources can be properly utilised. So, economy can grow up to its full extent. It can bring a new look to the economy.

(vi) Proper Distribution : Through deficit budget the Government enjoys scope to spend for the poor. Because of more effective employment, they can earn more. They can have better standard of living. As a result, the gap between the rich and the poor can be lessened.

(vii) Befitting for Emergency : A country confronts emergencies like war, natural calamities, epidemics etc. To face these emergencies, the Government requires to spend more. It can only be possible if it follows deficit budget. All these advantages of deficit budget present its importance as a fiscal policy. These confirm why deficit budget is a blessing for developing countries.

Demerits of Deficit Budget:  Deficit budget is not an unmixed blessing. It has got the following demerits.
(i) Inflationary : Deficit budget is prone to inflation. If it is not properly managed, there will be wide gap between demand and supply, Inflation will come up.

(ii) Less Export: Deficit budget creates inflation. So, price of the goods to be exported increases. The volume of export comes down. It will reduce the amount of foreign currency in the country.

(iii) Wasteful Expenditure : Deficti budget provides free hand to the Government to spend. There is every possibility of unproductive public expenditure. To be more popular the party in power will spend for its own benefit at the cost of the benefit of the economy. It leads to misutilisation of resources.

(iv) Debt Burden : The Government meets deficit through public debt. In case of deficit budget, all the debts are not spent on productive purposes. Those become burden to the community. The country enters into debt trap. It compels the country to make fresh debt to repay old debts. Despite its demerits, deficit budget has been always considered as an effective tool of growth and development in developing countries.

Group – C

Objective type Questions with Answers
I. Multiple Choice Questions with Answers :

Question 1.
Public finance deal with
(i) income & expenditure of the government
(ii) development of the state
(iii) individual welfare
(iv) all of the above
Answer:
(i) income & expenditure of the government

Question 2.
Which is not the objective of public finance?
(i) welfare of the state
(ii) maximisation of income
(iii) individual welfare
(iv) rational adjustment of income & expenditure
Answer:
(iii) individual welfare

Question 3.
Which is not in the subject matter of public finance?
(i) public expenditure
(ii) it has got general acceptability
(iii) public debt
(iv) all of the above
Answer:
(iv) individual income

Question 4.
Which budget is preferable for UDCs?
(i) currefl depOSit
(ii) fixed deposit
(iii) saving deposit
(iv) all of the above
Answer:
(ii) fixed deposit

Question 5.
What type of dep sit is appreciated by the business man?
(i) fixed deposit
(ii) saving deposit
(iii) deposit made with bonds & securities
(iv) None of these
Answer:
(iii) deposit made with bonds & securities

Question 6.
Public finance deals with the income and expenditure of the:
(i) Central Govt.
(ii) current deposit
(iii) Local Govt.
(iv) fixed deposit
Answer:
(iv) All of the above

Question 7.
Who adjusts expenditure to income :
(i) Govt.
(ii) current deposit
(iii) Both (i) and (ii)
(iv) recurring deposit
Answer:
(ii) Individual

Question 8.
Surplus budget is a cure for:
(i) Inflation
(ii) draft
(iii) Both (i) and (ii)
(iv) both (i) and (ii)
Answer:
(i) Inflation

Question 9.
Deficit budget is a cure for :
(i) Inflation
(ii) discounting bills of exchange
(iii) Both (i) and (ii)
(iv) direct loan
Answer:
(ii) Deflation.

Question 10.
Which is applicable to balance budget?
(i) It controls unnecessay expenditure
(ii) Does not creates economy crises
(iii) Does not creates inflation
(iv) All of the above
Answer:
(iv) All of the above

Question 11.
Which is the feature of deficit budget?
(i) Increases level of income and employment
(ii) Removes the unemployment problem
(iii) Eliminates deflationary pressure
(iv) All of the above
Answer:
(iv) All of the above

Question 12.
Which is the liability of the commercial banks?
(i) all types of deposits
(ii) authorised.capital
(iii) borrowing from other banks
(iv) all of the above
Answer:
(iv) all of the above

Question 13.
Which is not the asset of the commercial banks
(i) loans & advances
(ii) cash with RBI
(iii) Reserve funds
(iv) investments
Answer:
(iii) Reserve funds

Question 14.
Which is the most liquid asset of the commercial banks?
(i) cash in hand
(ii) saving deposit
(iii) loans and advances
(iv) investments
Answer:
(i) cash in hand

Question 15.
Which is not a function of central bank?
(i) lender of the last resort
(ii) advisor to the govt.
(iii) advances loan to people
(iv) custodian of foreign exchange
Answer:
(iii) advances loan to people

Question 16.
As monopoly of note issue, RBI prints all types of notes except
(i) two rupee notes
(ii) one rupee notes
(iii) five rupee notes
(iv) fifty rupee notes
Answer:
(ii) one rupee notes

Question 17.
Which notes are issued by Ministry of finance?
(i) one rupee notes
(ii) two rupee notes
(iii) five rupee notes
(iv) all of the above
Answer:
(i) one rupee notes

Question 18.
Which bank controls credit?
(i) RBI
(ii) SBI
(iii) Regional rural banks
(iv) all of the above
Answer:
(i) RBI

Question 19.
Which is a method of credit control?
(i) bank rate
(ii) open market operation
(iii) variable cash reserve ratio
(iv) all of the above
Answer:
(iv) all of the above

Question 20.
When Reserve Bank of India increases bank rate, the demand for loan
(i) increases
(ii) decreases
(iii) not affected
(iv) none of the above
Answer:
(ii) decreases

Question 21.
Barteris:
(i) Indirect exchange of goods against goods is called barter
(ii) Direct exchange of goods against goods is called bartar.
(iii) Both (i) and (ii)
(iv) None of the above
Answer:
(ii) Direct exchange of goods against goods is called bartar.

Question 22.
Deiine moeny:
(i) Money is what money does
(ii) Direct exchange of goods against goods in money
(iii) Anything that possesses general acceptability is money
(iv) None of the above
Answer:
(iii) Anything that possesses general acceptability is money

Question 23.
The function of money are:
(i) A medium and a measure
(ii) A standard and a store
(iii) Both (I) and (ii)
(iv) None of the above
Answer:
(iii) Both (1) and (ii)

Question 24.
Money serves as a link between:
(i) The present and past
(ii) The past and future
(iii) The present and future
(iv) None of the above
Answer:
(iii) The present and future

Question 25.
Moeny facilities:
(i) Barter transaction
(ii) credit trangaction
(iii) All of the above
(iv) None of the above
Answer:
(ii) credit transaction.

Question 26.
Example of near money is:
(i) Time or fixed deposits
(ii) Bills of exchange and Treasury bill
(iii) Stock and share
(iv) All of the above
Answer:
(I) All of the above

Question 27.
A command Bank has:
(i) Unlimited credit creation power
(ii) Limited credit creation power
(iii) All of the above
(iv) None of the above
Answer:
(ii) Limited credit creation power

Question 28.
Primary function of a commercial bank is:
(i) To finance Internal and External trade
(ii) Creation of moeny
(iii) Acceptance of deposits
(iv) None of the above
Answer:
(iii) Acceptance of deposits

Question 29.
The right-hand side of the balance sheet shows the items under the:
(i) Liabilities
(ii) Assets
(iii) Cash
(iv) None of the above
Answer:
(ii) Assets.

Question 30.
Cash-in-hand is otherwise known as:
(i) Till money
(ii) Cashin-vault
(iii) Both (i) and (ii)
(iv) None of the above
Answer:
(iii) Both (j) and (ii)

Question 31.
Moeny at call and short-notice is a:
(i) Long period loans
(ii) Very short term loans
(iii) Both (i) and (ii)
(iv) None of the above
Answer:
(i) Very short term loans

Question 32.
One rupee not is issued by:
(i) R. B. I
(ii) Commercial Bank
(iii) Govt. of India
(iv) None of the above
Answer:
(iii) Govt. of India

Question 33.
Time deposits are withdrawn:
(i) On the demand
(ii) After the expiry of the period
(iii) All of the above
(iv) None of the above
Answer:
(ii) After the expiry of the period

Question 34.
Most liquid asset of a commercial bank is:
(i) Demand deposits
(ii) Investment
(iii) Cash
(iv) None of the above
Answer:
(iii) Cash

Question 35.
Under which principle the central Bank of India issues notes:
(i) Proportional reserve system
(ii) Minimum reserve system
(iii) Maximum reserve system
(iv) None of the above
Answer:
(ii) Minimum reserve system

Question 36.
Quantitative credit control method refers to:
(i) Control the use of credit
(ii) Bring change in the total volume of credit in general
(iii) All of the above
(iv) None of the above
Answer:
(ii) Bring change in the total volume of credit in general

Question 37.
The selective credit control methods adopted by the central Bank to control credit are:
(i) Open market operation
(ii) Regulation of margin-requirements
(iii) Regulation on of consumers credit
(iv) Both (ii) and (iii)
Answer:
(i) Both (ii) and (iii)

Question 38.
The function of central Bank:
(i) Lender of the lust resort
(ii) Clearing agent
(iii) Banker’s Bank
(iv) Ail of the above
Answer:
(iv) All of the above

Question 39.
Central Bank acts as a financial advisor to the:
(i) General public
(ii) Commercial Banks
(iii) Govt.
(iv) None of the above
Answer: (iii) Govt.

II. Fill in the blanks :

Question 1.
_____ adjusts income to expenditure
Answer:
Government

Question 2.
_____ expenditure is compulsory in nature.
Answer:
Public

Question 3.
Government prefers _____ budget.
Answer:
deficit

Question 4.
_____ budget creates inflation. .
Answer:
deficit

Question 5.
_____ budget creates deflation.
Answer:
surplus

Question 6.
_____ budget does not create any economic crises.
Answer:
balanced

Question 7.
_____ budget is cure for inflation.
Answer:
surplus

Question 8.
_____ budget is preferred in under developed countries.
Answer:
deficit

Question 9.
_____ budget eliminates unemployement problem.
Answer:
deficit

Question 10.
_____ budget is a cure for deflation.
Answer:
deficit

III. Correct the Sentences :

Question 1.
Government adjusts expenditure to income.
Answer:
Incorrect
Correct: Government adjusts income to expenditure

Question 2.
Private expenditure is compulsory in nature.
Answer:
Incorrect.
Correct: Public expenditure is compulsory in nature.

Question 3.
Government prefers surplus budget.
Answer:
Incorrect.
Correct: Government prefers deficit budget.

Question 4.
Budget has been derived from a Greek word.
Answer:
Incorrect.
Correct: Budget has been derived from the French words.

Question 5.
Budget is always balanced.
Answer:
Incorrect
Correct: Budget may be balanced or unbalanced.

Question 6.
Budget is meant for a financial year.
Answer:
Correct

Question 7.
Deficit budget checks wasteful expenditure.
Answer:
Incorrect.
Correct: Balanced budget checks wasteful expenditure.

Question 8.
Price stability is assured in case of surplus budget.
Answer:
Incorrect.
Correct: Price stability is assured in case of balanced budget.

Question 9.
Balanced budget controls public debt.
Answer:
Correct.

Question 10.
Surplus budget increases national income .
Answer:
Incorrect.
Correct: Deficit budget increases national income.

Question 11.
In surplus budget. Government receipts are higher than government expenditure.
Answer:
Correct.

Question 12.
Surplus budget controls unemployment.
Answer:
Incorrect.
Correct: Deficit budget controls unemployment.

Question 13.
Surplus budget leads to maximum utilisation of resources.
Answer:
Incorrect
Correct: Deficit budget leads to maximum utilisation of resources.

Question 14.
Deficit budget is contractionary; but surplus budget is expansionary
Answer:
Incorrect.
Correct: Surplus budget is contractionary but deficit budget is expansionary.

Question 15.
Surplus budget increases debt burden.
Answer:
Incorrect
Correct: Deficit budget increases debt burden.

Question 16.
Surplus budget checks unproductive expenditure.
Answer:
Correct

Question 17.
Deficit budget is inflationary.
Answer:
Correct.

Question 18.
In deficit budget price of exported goods increases.
Answer:
Correct

IV. Answer the following questions in one word :

Question 1.
What is public finance?
Answer:
Public finance is a subject that deals with the income and expenditure of the government.

Question 2.
Write a similarity that exists in both public finance & private finance.
Answer:
Both public finance & private finance have same objective i.e. satisfaction of human wants.

Question 3.
What is budget?
Answer:
Budget is the annual financial statement of the anticipated receipts & expenditure of the government for a financial year. ‘

Question 4.
From which word, the term ‘Budget’ is derived?
Answer:
The term budget is derived from the French word “Budgett”, which means small leather bag.

Question 5.
What is consolidated fund?
Answer:
Consolidated fund consists of all revenues & loan received by the government.

Question 6.
What is balanced budget?
Answer:
Balanced budget is that budget in which the anticipated receipts & expenditure of the government are equal.

Question 7.
State one merit of the balanced budget?
Answer:
Balanced budget checks unproductive expenditure.

Question 8.
What is deficit budget?
Answer:
If the estimated revenue falls short of the estimated expenditure in the budget period, it is called deficit budget.

Question 9.
What is surplus budget?
Answer:
In surplus budget, the anticipated government receipts are higher than the government expenditure during the budget period.

Question 10.
What type of budget is framed in UDCS?
Answer:
UDCS frame deficit budget.

Question 11.
Give a demerit of deficit budget?
Answer:
Deficit budget is inflationary in nature.

Question 12.
Which budget leads to maximum utilisation of resources?
Answer:
Deficit budget.

Odisha State Board CHSE Odisha Class 12 Economics Solutions Chapter 12 Money and Banking Questions and Answers.

CHSE Odisha 12th Class Economics Chapter 12 Question Answer Money and Banking

Group – A

Short type Questions with Answers
I. Answer with in Two/Three sentence.

Question 1.
Money facilitates credit transaction.
Answer:
Money acts as standard of deferred payment & on account of this, anybody can postpone its payment for current transaction & pay it in future. It shows that money facilitates credit transaction.

Question 2.
Money is what money does.
Answer:
Money performs a wide variety of functions almost in all fields, money has got certain role to play. So it is rightly told money is what money does.

Question 3.
Bank drafts & cheques are near money.
Answer:
Bank drafts & cheques perform the functions of money; but these are not so liquid nor legal tender like money. So there are named as near money.

Question 4.
Every loan creates a deposit.
Answer:
When any person gets loan from a bank, the t^ank opens an account in the name of this borrower & frrom this account the borrower withdraws the money. So every loan creates a deposit.

Question 5.
Current deposit does not bear any interest.
Answer:
Current deposit is such a deposit which can be withdrawn at any date during the banking hours without having any restriction or early information. Because of such high frequency of withdrawal, the bank does not pay any interest.

Question 6.
Comercial banks are the agents of economic development.
Answer:
Commercial banks mobilises the saving of the individuals & invest money in productive channels. So commercial banks are called the agents of economic development.

Question 7.
Central bank is the lender of the last resort.
Answer:
When any commercial bank is under the crunch of financial bankruptcy, the central bank gives loan to the commercial bank for its revival. So it is called the lender of the last resort.

Question 8.
Central bank is the bankers’ bank.
Answer:
Central bank guides, advises & frames rules for the commercial banks. It also keeps a fraction of deposit of commercial banks with itself to meet the emergency & also determines the bank rate & controls the credit. So, it is called bankrs bank. .

Question 9.
Central bank is the bank of the government.
Answer:
Central bank guides, advises & suggests the government for its smooth functioning of economic system. It gives loan to the government & directly deal with the problem of the government. So, it is called as the bank of the government.

Question 10.
Central bank controls credit.
Answer:
When there is credit expansion made by the commercial banks, the central banks comes forward to control it through its monetary & fiscal operation alongwith certain selective’ credit control measures. The central bank thus, controls credit.

Question 11.
Central bank is the apex bank.
Answer:
In monetary affair, central bank plays a vital role in banking business. It controls, guides & advises the commercial banks. So it is called apex bank.

Question 12.
Money facilitates credit transaction.
Answer:
Money acts as a standard of deferred payment as well as a store of value. So it can facilitate credit transaction.

Question 13.
Near money is optional.
Answer:
Near money though performs certain functions of money; yet it lacks liquidity and legal approval in respect of universal acceptability. So it is optional.

Question 14.
Bank money is not legal tender.
Answer:
Bank money like draft and cheque do not have universal acceptability and also lack liquidity like money. So it is quite optional because of legal approval.

Question 15.
Commercial banks create credit.
Answer:
Commercial banks can give loan to the borrower which can be disburbed through opening an account. Thus commercial bank gets scope to create credit.

Question 16.
Central Bank is the bankers bank.
Answer:
Central bank guides advises and suggests the commercial banks with regard to monetary transactions. These banks keeps a fraction of their deposit with central bank to create credibility and reliability among the customers. So central bank is the bankers bank.

Question 17.
Central bank has the monopoly of note-issue.
Answer:
Central bank is the apex bank which controls the money supply in the economy. In order maintain uniformity in the money supply and to control economic hazards, the central bank enjoys the monopoly of note issue.

Question 18.
Central bank is the lender of the last report.
Answer:
Central bank gives loan to the commercial bank at the time of its need. When commercial banks becomes bankrupt, central banks comes forward to help these banks for their revival. So the central bank is called the lender of the last resort.

II. Answer with in Five/Six sentence :

Question 1.
Money acts as a standard of deferred payments. Explain.
Answer:
Money possesses the feature of ‘general acceptability’. Hence, it is quite natural that money facilitates the deferred payments. In other words, money, being the medium of exchange, facilitates the credit transaction through its function as a standard of deferred payments. But for this, money must maintain a constant value through time.

Question 2.
What is Near Money?
Answer:
Money consists of legal tender money and bank money. In case of big transactions where large payments are involved bank money in the form of bank drafts, bank cheques is used. In modem economies, bank money plays a vital role and forms a major proportion of money supply.

There are other assets which cannot be technically regarded as money but are claims to money and perform some functions of money. Such assets one called ‘ Near Money’. Near Money refers to all those assets which possess many of the features of money, have high degree of liquidity, and can be easily converted into maoney. Near money cannot be directly used for making transactions. This must be converted into money proper before use. Near money assets are highly liquid but is not as liquid as the money is. They are close substitutes of money but not the perfect substitutes. Some examples of near money are Bills of Exchange, Bonds, Debentures, shares etc.

Question 3.
Distinguish between Money and Near Money.
Answer:
The distinction between money and near money can be expressed on the following grounds.
(i) Definition – Money consists of coins, currencies and demand deposits of the banks whereas Near Money includes the financial assets like time deposits, bills of exchanges, bonds, equity shares etc.

(ii) Liquidity- Money is found to be highly liquid in comparison to Near Money.

(iii) Function – Money serves as a Unit of Account or a common measure of value. But Near Money does not perform such functions.

(iv) Transaction- Money can be spent directly for making any sorts of transaction but Near money lacks this; rather it should be converted into money proper before its use.

Question 4.
Show that Money and Near Money are similar.
Answer:
Both the Money and Near money are claims. Money proper like, coins and currency notes are claims over the government and Central Bank. Near money assets are claims over their respective parties or institutions. Secondly, liquidity is the common attribute of both money and near money. Lastly, both money and near money act as a store of value.

Question 5.
What is current deposit?
Answer:
Current deposit is that deposit which can be withdrawn in as many times and in as much amount as desired by the depositor. Normally no interest is paid on these deposits. Current deposits are otherwise called Demand Deposits and are very much popular among the businessmen and traders.

Question 6.
What is cash credit?
Answer:
Cash credit is a type of loan given to the borrower against his current assets such as shares, stocks, bonds etc. Such loans are not based on personal security. The bank opens an account in the name of the borrower and allows him to withdraw the sanctioned amount from time to time up to a certain limit as determined as the value of his current assets. Interest is charged only on the amount withdrawn.

Question 7.
What is overdraft?
Answer:
Overdraft is a system adopted by the Commercial Banks to advance loans to its depositors over and above their amount deposited. Under this facility, the customers of the bank are allowed to withdraw more amount than their deposits. Interest is charged from the customers on the overdrawn amount.

Question 8.
Commercial Banks create credit. Explain.
Answer:
Credit creation is a unique function of the commercial banks. Credit creation is the natural outcome of the process of advancing loans as adopted by the banks. When a bank advances a loan to its customers, it does not lend cash but opens an account in his name, and credits the amount of loan to this account. Thus, whenever a bank grants a loan, it creates an equal amount of bank deposit creation and such deposit is called credit creation which results in a net increase in the money stock of the economy.
Banks have the ability to create credit many times more than their deposits.

Question 9.
Write a short note on “Lender of the Last Resort”
Answer:
As an apex bank and banker’s bank, the Central Bank acts as the lender of the last resort. Whenever, the commercial banks are not able to meet their financial requirements from any other source, they approach the Central Bank for financial accommodation. The Central Bank provides such financial accommodation to the Commercial Banks by rediscounting their eligible securities and exchange bills. Thus, the Central Bank is considered to be the ‘Lender of the Last Resort”

Question 10.
Write a short note on “Banker’s Bank”.
Answer:
The Central Bank acts as the ‘Bankers’ Bank” in three capacities such as (a) a custodian of the cash reserves of the Commercial Banks, (b) the Lender of the Last Resort and (c) as clearing agent. As a custodian of the cash reserves, the Central Bank maintains the cash reserves of the Commercial Banks. Every Commercial Bank has to keep a certain percentage of its cash balances as deposits with the Central Bank. Thgse cash reserves are utilised at the time of urgency raised by the Commercial Banks. Since all the banks have their accounts with the Central Bank, the Central Bank can easily settle the claims of the commercial basis. Hence, the Central Bank acts both as the lender of the last resort and as a clearing agent for the Commercial Banks.

Question 11.
Write a short note on “Cash credit”.
Answer:
Cash credit is tfie credit granted against the borrower’s promissory notes guaranteed by at least two securities. Sometimes it is supported by a pledge of securities or goods. In such cases, if advances are sanctioned, the bank opens an account in the name of the borrower & the loan amount is credited to this account. The borrower pays the interest on the amount already withdrawn. This is very popular amongst the business man.

Question 12.
Write a short note on “Fixed deposit”.
Answer:
The deposits which are made for fixed period of time are called fixed deposits. There deposits can not be with drawn before the expiry of the period. The bank utilises these deposits in profitable channels & also pays higher rate of interest. These deposits are other wise called time deposits.

Group – B

Long Type Questions With Answers

Question 1.
What are the functions of money?
Answer:
Economic activities have become complex and aggravated the difficulties of barter. Barter has become unsuitable under the modems economic condition. So the device of money has been adopted to over come the drawbacks of the barter system. The following are the functions of money:

(i) A Medium of Exchange : The most important function of money is that it serves as a medium of exchange. Now a weaver does not directly exchange his cloth for com. He exchanges it for money. Then he converts his money into com. So if the weaver wants com, her first converts his cloth into money and then money into com. Money comes in between the exchange of the two commodities and act as a medium of exchange. Thus, it eliminates the greatest disadvantage of barter namely, the necessity of double coincidence of wants. This function of money is of greatest economic value. Now-a-days, the wheels of commerce move quickly because there is money which acts as medium of exchange.

(ii) Measure of Value : The value of commodities can be accurately expressed in terms of money. Money works as a common denominator and the values of all commodities can be compared. This facilitates exchnages – Just as we measure the cloth with a yard stick, we measure the values of commodities with money. This function of money removes another disadvantge of barter system namely, the difficulty of measuring the value of commodities. We can keep accounts and enter into contracts in terms of money. Hence money is also called standard of account.

(iii) Standard of Deferred Payments : Borrowing and lending are the important features of modem economy. Commodities and services are taken in advance and payments are made later on. Many transactions are done by means of credit. This is made possible because there is money economy. Without money, we cannot imagine borrowing and lending. Debts and interest on debts can be accurately calculated in terms of money. Uniform price (money interest) for a uniform service (money lending) is made possible by money. Comparatively great stability in value of money aids this function.

(iv) Store of value : Most of the commodities or service can not be store for long. They perish in course of time and lose their value. For e^mple, a labour can not store his labour. He can not make any provisions for old age or period of sickness, if there is no money economy. Now he can convert labour into money and store his money for any length of time. Money doesn’t easily perish and its value does not violently change. Money can also be kept as a liquid asset since it is useful for making ready payments.

There will mot be any incentive for savings and investments it there is no device of money as store of value, Money functions as a standard of store becuase it has got the quality of standard of deferred payments. These last two functions Jof money are interdependent. Without money we cannot imagine manufacture* employing thousands of workers in manufacturing automobiles or building ships. Payments are made to workers in money. Raw materials are purchased with money and the final product is sold for money. There are four functions of money. “All these so called functions money are simply different, but related aspects of the fact that the use of money is essential to a community based on division of labour and exchange.” (Benham)

Question 2.
What are the functions of commercial bank?
Or
Explain the services of a commercial bank.
Answer:
Commerical bank perform a number of services. Their services can be broadly classified under two heads,
(i) Primary services
(ii) Subsidiary and miscellaneous services.

Primary Services of a Commercial Bank: Banks do not borrow funds in the normal way. They adopt different types of technique. They borrow funds by accepting deposits.

These deposits are of three types. They are fixed deposits, current account deposits and savings bank deposits. Under fixed deposit system, the depositor agrees to keep his money with the bank for as agreed period. He is not allowed to withdraw the money before the expiry of the period. He gets interest on the money for the period. Rich people keep their money with the banks under fixed deposit accounts.

Under current account system, the depositor is allowed to withdraw money upto the deposit amount at any time during the banking hours. Traders and businessmen keep their money with banks under current accounts. All the depositors don’t withdraw their money at the same time. So a banker can use a large part of the money or current accounts for profitable purpose.

Savings bank deposits are intended to make small income groups save something out of their monthly incomes. Banks accept even small amounts under savings deposits. The customers are allowed to withdraw money. But restrictions are placed on such withdrawals.
The banks receive large volume of funds through these deposit accounts from a wide range of people. They pool together the small and scattered amounts of money from large number of people and make them available as loans to trade and industry. Such scattered amounts would remain idle but for banks. Thus banks render three heads. They are overdrafts, cash credits and direct loans.

Overdrafts : Sometimes a customer is allowed to withdraw more than what he has deposited. In this case the bank is said to allow overdraft. The bank charges interest on the amount which is overdrawn by the customer.

Cash Credits : The loan amount is not directly handed over to the customer. A current account is opened in his name and the loan is placed to the credit of his account. The customer can withdraw this amount by cheques according to his need. Interest is calculated not on the total amount of the loan, but oh the amount which is actually utilised by the customer. However, the bank collects some minimum interest wheather the customer makes use of the funds at his disposal or not. Traders prefer cash credits to ordinary loans. Banks also prefer cash credits because they need not pay the entire amount of the loan on the same day. The customer is asked to withdraw the amount by cheques gradually. On the whole, cash credits are very popular in India.

Ordinary Loans : the borrower lodges some securities with the bank and takes the loan amount. The borrower has to pay interest on the entire amount from the date of taking the loan to the date of repayment. Banks also provide lonas to the customers by discouting bills of exchange.

Subsidiary Services of the bankers:
Demand drafts : Banks issue drafts and facilitate remittance of funds from one place to another. When large sums of money have to be sent from one place to another. It is not economical to send them by money order. The best way is to employ the bank as the agent of remittance by purchasing demand draft. The bank collects charges for issuing drafts.

Collection of cheques, bills, pay orders etc of customers : Commercial banks undertake to pay subscriptions insurance premium, rents etc. on behalf of their customers on their standing orders. They make such payment and debit the accounts of their customers. Similarly, banks collect subscriptions, insurance premium or rent etc. on behalf of their customers and credit their accounts. Trustees, executors and attorneys etc: Banks undertake to act as trustees, executors and attorneys on behalf of their customers, if they are authorised to do so.

Purchasing ans selling Securities : Banks also undertake to purchase or sell securities on behalf of their customer. They advice their customers in the matfers of investment.

Issue of letters of credit, circular letters, traveller’s cheques etc : Banks issue letters of credit to the customers and facilitate trade connections with foreign countries. Circular letters are issued to tourists. It is not safe to carry money in person. When a circular letter is taken from a bank, the customer can get cash from banks situated at different places. The issuing bank makes previous arrangements with different banks at different places.

Safe custody deposits : Commercial banks receive valuables such as jewels etc. for safe custody. The banks maintain strong valuts for this purpose. They charges small fee for this services.

Trade references : When a trader wants to establish business connections with a new client be seeks information regarding financial standing and business reputation of his new client. Banks provide such information regarding the business reputation and the standing of their customers on thier request.

Question 3.
Explain the various types of deposits of a commercial bank.
Answer:
The most important function of a commercial bank is to borrow funds from the people and lend them to the people who are in need of them. Bnaks do not borrow funds from the public in the ordinary way They borrow funds through deposits. Bnaks make attempts to attract funds from a wide range of people. They offer different terms to different classes of people for attracting deposits.
The banker’s deposits may be classified under four heads depending on such terms. They are (a) fixed deposits (b) current account deposits (c) savings bank deposits and (d) seasonal deposits.

Fixed Deposits : Under this system, the customers agree to keep their funds with the bankers for a definite period say 1 month, 3 month, 6 month etc. They are not allowed to withdraw this amount within this stipulated period. These funds are at the disposal of the bank till the end of the agreed period. The banker can utillise them for profitable purposes. These deposits are also called time deposits. Some banks allow their customers to with draw these deposits after giving a week’s notice, or fifteen days notice. Banks give interest to the customers on the fixed deposit amounts. People who have surplus funds and who are not able to invest their funds otherwise, keep their money in fixed deposit accounts with a bank. Banks receive large volumes of funds on fixed deposits accounts.

Current account deposits : Under this system, the depositors are allowed to withdraw their money at any time during banking hours. There are traders, manufacturers and other people having large volume of funds. But they can not afford to lock up thier funds in fixed deposit accounts. They require money constantly for business purpose. Banks attract funds from such types of people through current account deposits, The depositor is given a cheque book. He can withdraw money any number of times through cheques.

He is also given a pass book in which all transactions between him and the banker are recorded. Traders generally keep their money in current account deposits and make their payment through cheques. Banks receive large volume of funds under this head. Though customer have a right to withdraw money from their accounts, the banker know by experience that all the customers do not withdraw on the same day. Some customers will be withdrawing and some will be depositing. When a customer pays another customer by cheque, the business of the banker is to transfer the amount of the cheque from the account of one person to that of the other. Such transfer of transactions are called transfer transactions. Such transfer transactions will be more common than actual cash transactions.

On the whole, a banker finds it possible to invest a greater portion of the funds received on current accounts for profitable purposes.
Savings bank deposits: Under this system, people with small incomes are encourged to save what all they can. Deposits of even small amounts are accepted. The depositors are allowed to withdraw money from their accounts. But the bank imposes some restrictions on their withdraw is Banks in India do not allow their customer of this class to withdraw more than twice in a week. Further they are not allowed to withdraw more than 2000 rupees in any week, unless a special notice to that effect is given.

Savings bank account faculties encourage thrift among public especially people with small incomes. Banks give intrest of 214 to 3 percent on the monthly minimum balance maintained by the customers. Commercial banks get a very large volume of funds under this head. Owing to restrictions on withdrawas they can utilize a large part of these funds for profitable purposes.

Seasonal deposits: In the agricultural countries there will be heavy demand for loans during a particular season. To meet the demand for loans, commercial banks attract deposits by special inducements in the shape of higher interest during that season. These deposits resemble fixed deposits. They are accepted for a particular period. Withdrawl are not allowed before the stipulated period. But these deposits are not allowed to stand after the season.

Briaks also attract funds by selling cash certificate. Thus Banks attract funds by way of deposits and render a very useful services to the society. But for the banks such funds would have remained scattered with the people. Banks pool such scattered funds and make them available to industry and trade.

Question 4.
Explain how banks create credit? What are the limits to the powers of the banker in creating credit?
Answer:
A Banker is said to create credit when he credits the deposit accounts of his customer on aquiring assets other than cash, such as over drafts, cash credits bills and stocks. The bank clerk simply credits the deposit accounts of the customer who take loans under overdrafts or cash credit arrangement. The credit balance with a banker is as good as money. So it is said that banks create credit is the creation of bank clerk’s pen.

A banker acquires profitable assets in the process of creation of credit. But he can not go on acquiring such assets in exchange for his credit entries. There are certain factors which limit the capacity of a banker in creating credit. Following are Such factors :

(a) Supply of legal-tender money : Credit transactions do not end by themselves. They resolve into cash transactions at one time on the other. So the banker must maintain adequate cash reserves to meet the demand obligations of his customers. The banker knows by experience, the minimum percentage of cash to deposits, which he has to maintain to meet the withdrawals of his customers. Failure to maintain this safety minimum will land the banker in troubles – For example, a banker can create credit up to ten times the cash reserve if the conventional and needed percentage of cash to deposits is ten.

So credit depends on the available supply of cash in the values o the bank. The cash reserves of the commercial banks depend on the total supply of money in circulation and its velocity. The central bank is the institution which controls the volume money and its velocity circulation. The commercial banks have no control over the legal tender money. So they have to adjust the volume of their credit to the available supply of the legal tender money which they acquire in the ordinary course of banking through share capital.

(b) Popularity of cheque currency : In countries where cheques are popular, cash withdrawals will be less. There will be more transfer transactions. So the banker can manage the business with a low percentage of cash to deposits. This enables the banker to create credit extensively. On the other hand, in a country where cheque system is not popular, more cheques will be presented at the counter for encashment. The banker must maintain a high percentage of cash to deposit. This reduces the capacity of a banker to create credit.

(c) Statutory reserve ratios : Commercial banks have to maintain some minimum percentage of cash to deposit in their accounts with the central banks. This is a statutory obligation imposed on commercial banks in several countries. The central bank can impose penalty on banks which fail to maintain the statutory mimimum. Central banks have discretion to vary the reserve ratio alos. Banks have to adjust their-deposit liabilities in conformity with the statutory ratio.

(d) Trade activity : During the periods of rising prices, the trade conditions appear rosy and traders borrow loans on a large scale to finance their trade activities. So there will be increased demand for bank credit and banks expand credit.

(e) Policy of the Central Bank: CentraTbank is armed with weapons to control the credit created by the commercial banks. Bank credit constitutes purchasing power. When banks expand credit discriminately in the prices tend to rise and the symptoms of inflation appear. The central bank is charged with the function of correcting such a situation The central bank employs its conventional weapons such as bank rate or open market operations etc and tries to control the activities of the commercial banks in creating credit. Commercial banks ultimately have to fall in line with the credit policy of the central bank.

(f) Liquidity Preference of the People : The capacity of commercial banks to create credit also depends on the degree of preference of the people to hold liquid cash. The degree of liquidity preference is influenced by certain economic and speculative considerations. Banks have to adjust their credit in accordance with the liquidity preference of the people.

So the supply of cash in the vaults of a commercial bank is influenced by the above factors and the banker has to adjust his deposit liabilities in accordance with the volume of cash reserves.

Do banks Create Credit ? : The banker creates credit when he grants a loan to a customer under overdraft or cash credit arrangement. The loan amount is not given to the customer in the shape of cash immediately. The loan amount is placed to the credit of the customer and the customer is asked to withdraw the amount through cheques whenever he needs the money. Similarly the banker creates credit when he purchases a bill or a stock from a customer and places the amount to the credit of the customer.

The customer is satisfied with the credit entry in his favour. He does not insist on immediate cash payment. So the banker is able to create credit because the customer is willing to keep the money with the banker. This willingness of the customer to retain the cash with the banker. This willingness of the customer to retain the cash with the bank enables the banker to create credit.

Certain writers like Walter leaf and Cannan say that the initiative in the creation of credit does not lne with the banker. It lies with the customer who is willing to retain the money with the banker. Hartley withers on the otherhand, says that the initiative in the creation of credit lies with the banker as “loans make deposits”. When a banker advances a loan he is crediting the deposit account of the customer. Hence loans in one shape or the other increase the deposit liabilities.

But it is true that if the customer demand cash immediately, there will not be an increase in the deposits. But in the countries where banking habit is well developed, payment are usally made through cheques. Borrowers prefer to keep the amount of loan with the banker and issue cheques against it.

If the payee of the cheque also happens to be the customer of the same bank, his deposit will increase to the extent of his cheque amount and the account of the drawer will decrease to that extent. Hence the total deposit liabilities will continue to be at the same figure, so long as the loan remains. If the payee happens to be the customer of another bank, the deposit liabilities of the second bank will rise. In either case, the increase in the deposit is the result of the loan.

But according to Walter Leaf and cannan, the initiative in the creation of credit does not lie with the banker. The banker is able to lend money because the depositors are not withdrawing cash from their accounts. So the banker is only lending what others have left with him. Leaf compares the transactions of a bank with a cloakroom. Suppose there are 100 guests to an evening party. Each of them has brought a cloak which is deposited with cloakroom attendent. Suppose the cloakroom attendend knows that the party does not break up before 10 p.m. The attendent can loam out a greater portion of the cloaks, say 80 cloaks on the conditiob that they should be returned by 9-30 p.m. If by chance any guest departs before 10 p.m. he can give one of the cloaks that arejceept in reserve.

In this case, we can not say that the cloak room attendent has created 80 cloaks. He has’ simply loaned out the cloaks that are kept with him. Similarly, we cannot say that the banker is creating deposits. He is only lending the funds that are deposited with him by some customers.

It is true that the willingness of the customers to keep their deposits with the banker is helping him to create credit. A customer keeps the money with the banker, because he has confidence in the banker’s ability to repay the amount, when he demands it. The banker is infusing confidence into the customer. Hence, we may say that the banker is creating credit.

Question 5.
What are the functions of a central bank?
Answer:
A central bank is the most important institution of money market. There will be one central bank for each country. The International Monetary Conference held in Brussels in 1920 recommended the establishment of a central bank in each country where there was none. A central bank is usally owhed and managed by the government. Even if is owned by private individuals, the government takes an active part in its management.

A central bank has distinct functions of its own. Generally it is not allowed to perform the functions of a commercial bank Or compete with commercial banks. The functions of a central bank are very vital to the economy of a country. It is given monopoly in the discharge of its functions. The functions of a central bank are given below.

(i) Note Issue : Issuing of notes is one of the most important functions of a central bank. It is usally given monopoly in issuing notes. A central bank as a note issuing authority is expected to maintain stability in the value of currency. There are different methods of issuing notes such as fixed fiduciary system, maximum fiduciary system, proportional reserve system, variation of the proportional reserve system and minimum reserve system.

A central bank may adopt any one of these systems depending upon the economic conditions of the counrty. A central bank issues notes consistent with the principles of safety and elasticity. Usally, the government lays down the principle of note-issue. Some countries prescribe a gold clause against note-issue. Then the central bank has to maintain the prescribed ratio of gold to notes. Whatever be the principle, it is the duty of central bank to maintain the internal and external value of its currency.

(ii) Banker to the Government: A central bank acts as a banker to the government. It maintains the accounts of the government. It enjoys monopoly in this respect. It receives the revenues and makes disbursements on behalf of the government. It maintains public debt registers, it helps the government in raising loans, in making interest payments and in redemption of loans It also grants short period loans to the government. It acts as a financial advisor and foreign exchanges.

(iii) Banker to the Commercial banks : Acentral bank is regarded as a philosopher, a guide and an advisor to other commercial banks. Commercial banks maintain accounts with the central bank either by tradition or by statutory obligation. Commercial banks consider it a matter of prestige to come into contact wih the central bank. The central bank looks into the affairs of the commercial banks and raises the general standard of banking. It offers remittance facilities to the commercial banks.

A central bank manages the clearing house. A clearing house is a place where banks settle their indebtedness arising out of inter-book transactions. The central bank provides clearance facilities by managing of the clearing house. Clearance facilities enable the commercial banks to economise the cash reserves.

Central banks acts as a lender of the last resort. It lends funds to the (pnmercial banks and helps them to tide over the difficulties. It advances loans against eligible securities or rediscounts first class bills of the commercial banks. The functions of the central bank increases the structural stability of the banking system. It also increases the liquidity of some of the bankers assets.

Central bank acts as a custodians of the national reserves. A single reserve in the hands of the central bank is not only economical but also very effective in meeting emergencies. All commercial banks have to maintain some balances in their accounts with the commercial bank. The government also maintains a minumum balance in its account with the central bank. All these funds constitute national reserves. Besides the central bank has to maintain a minimum gold reserve under statutes and also foreign currencies. These can be effectively employed to meet any national emergency.

(iv) Controlling of credit: This is another important function of a central bank. A central bank has to regulate the credit created by commercial banks. Commercial banks sometimes create credit indiscriminately in their anxiety to get more profits or to avoid losses. Such indiscriminate expansion or contraction of credit is affects price level, empolyment, foreign trade etc. So it is the duty of the central bank to regulate credit and maintain stability in the value of currency and other economic conditions. The central bank has several weapon to control credit. They are (1) the bank rate (2) open market operations (3) variation of the reserve ratios (4) rationing of the credit. (5) direct action and moral suasion.

Bank rate is the official minimum rate at which the central bank undertakes to rediscount first class bills or advance loans against eligible securities to the commercial banks. When the central bank thinks that the commercial banks are expanding credit unduly. It raises the bank rate. Commercial bank also raise their own rate of interest since the central bank is the lender of last resort. The borrowers find that the bank loans have become costly. So they reduce their borrowings from the bank. That is how credit is controlled through bank rate policy. Sometimes bank rate policy doesn’t work successfully especially when there are large volume of idle funds with the commercial banks. Then the central bank employs open market operations.

Open market operations consist of selling or buying eligible securities in the open market. The central bank withdraws money from circulation or puts more money into circulation by open market operations. When the central bank wants to curtail the bank credit, it sells securities. The investors make payments to the central bank by drawing from their deposit accounts. Thus, the central bank withdraws money from circulation. The banks find that their cash reserve have fallen. So they reduce their lendings. Similarly when the central bank wants to expand credit, it buys securities and releases more money into circulation. The money goes to the commercial banks by way of deposits. They increase their lendings as their cash reserves.

When the money market is not well organised, bank rate policy and open market operations do not work successfully.. Then the central bank employs another weapon called, the variation of the reservation. All commercial banks have to maintain on their accounts with the central bank, cash balance equal to a certain minimum percentage of their deposit liabilities. The percentage is called reservation. When the Central bank wants to control the credit changes the reserve ratio, it compels the commercial banks to maintain a higher percentage of cash balance in their accounts. The commercial banks have to remit cash to maintain the required percentage of balance. Their cash o n hand windless. So they have to reduce their lending. This is a drastic weapon in the hands of central bank to control credit.

The central banks also controls credit by the rationing of credit. The central bank fixed the quota for each commercial bank and gives accommodation only up to the quota fixed. The commercial banks adjust their loans to the traders on the basis of this quota. Sometimes the central bank may reject to rediscount certain class of trade bills. This also affect the pattern of lending of the commercial banks. This type of credit control is rarely effective and has to be used in exceptional circumstances.

A central bank can also control credit by moral persuasion. It sends directives to the commercial banks requesting them to control credit in the interest of the nation. This proves to be an effective method of credit control, if the commercial banks comply with the request of the central bank. This depends upon the prestige and the strength of central bank. If the commercial banks fail to comply with such request then the central bank may resort to direct action to control credit. Direct action involves a threat. But threats are unpopular in controlling credit.

Thus a central bank is armed with several weapons to control the credit and it is the responsibility of the central bank to regulate the credit in the best interest of the country. It safeguards the foreign trade through its credit policies. In addition to the above functions, some centra banks are charged with special functions. A central bank may be specially charged with the function of maintaining the external value of the currency. The Bank of England is asked to maintain a separ and fund called Exchange Equilisation Fund for the purpose.

The Reserve Bank of India is charged with the function of developing rural credit. It is asked to maintain a statutory department called “Agricultural credit Department” to find out ways and means to develop rural credit and to co-ordinate the activities of the various institution that supply rural credit.

Central banks are also expected to lend support to the governments in all nation-building activities and in implementing various economic plAnswer: Thus, the central bank is a very important institution and is very vital to the economic well being as a nation.

Question 6.
Explains the functions of a central bank as
(a) banker to the government and
(b) banker to other banks.
Answer:
(a) Banker to the Government: One of the important function of a central bank is to act as a banker to the government. The government is the lagest dealer in the currency and in foreign exchanges. So if the central bank is to maintain internal and exteranl stability in the value of currency, it must maintain the funds of the government. It is also convenient and economical to the state to entrust the management of its funds to the central bank. In some countries, the monopoly of government funds is enjoyed by the central bank as a matter of tradition. In most countries the relation between the state and bank is governed by the statutes.The government receives large revenues and spends huge amounts of money. Unless the central bank acts as a banker to the state, it cann’t adjust the supply of money to its demand and it can not fulfil some of its other functions successfully.

As a banker to the government, the central bank maintain account of various government such as the central government, state government local government etc. It receives revenues on behalf of the governments, and makes disbursements on behalf of the government, ft helps the government in raising loans. It managed the public debts and maintains transfer registers in respect of government stock and certificates. It helps the government interest payments on the loans and in the redemption of loans. It provides the government with foreign exchanges. It grants temporary loans to the governments. The receipts of the government are seasonal. But the expenditure of the government is spread out evenly throughout the year. The central bank helps the government in the adjustment of the revenue to the expenditure by granting short period loans.

Sometimes the bank also helps the government in raising short-term loans by re-discounting treasury bills directly or indirectly, when they are presented through the commercial banks. This is the easiest way for a government to raise short period loans. It manages exchange – clearances and collect statistics of various kinds of financial matters and makes them available to the government. It maintain considerable metallic reserves to meet contingencies.

It co-operates with the government in all the nation-building activities. It also help the government in the promotion of certain special interest which are necessary for the welfare of the country such as development of agricultural credit etc. as in India. It maintains research departments to study various financial problems that confront the government and it acts as a financial advisor to the government.

(b) Banker to the other banks : Commercial banks and other members of the money market maintain accounts with the central bank either by tradition or by statute. They have to maintain a certain minimum percentage of their liabilities in their accounts with the central bank.

A commercial bank derives the following advantages by maintaining an acount withe the cental bank:

1. A central bank is the most important institution in the money market. It is regarded as a mother institution by the commercial banks. It is the banker to the government. So a commercial bank regards it as a matter of prestige to come into contact with the central bank.
2. A bank must satisfy some conditions laid down by a central bank to become its customer.
3. A commercial bank that maintains accounts with the central bank gains the confidence of the public.
4. The central bank managing the clearing house. Generally a commercial bank that has an account with the central bank is eligible to become member of a clearing house. It can settle the inner bank and thus economise the use of cash reserves.
5. The central bank also helps the commercial banks in the matter pf remittance of funds free of cost or at an exceptionally low rate of commission.
6. A Commercial bank can secure loans from the central bank in times of need.

A central bank gets the following advantages by accepting accounts from the commercial banks :

1. It can watch the activities of the commercial banks through their accounts.
2. It can raise the general standard of banking by giving advices to its members.
3. It gets large volume of cash reserves from the deposits of the commercial banks. It can employ these funds in assisting the commercial banks it times of crisis.
4. A central bank can study the position of commercial banks at the clearing house. It can give a timely warning to a bank that faces adverse clearance continuously.
5. A central bank can control the credit of the commercial banks through their accounts. The commercial banks have to maintain certain minimum cash balances in their accounts with the Central bank. By verifying this minimum, the central bank exercises control over the credit of the commercial banks.

The member banks have to submit periodical returns to the central bank. They enable the central bank to collect satistics of various types on banking activities. It can study the general level of banking and give advice to the members. The central bank is regarded by the commercial banks as a guide, friend and philosopher.

Question 7.
Difference between Central Bank and Commercial Banks.
Answer:
There are certain basic differences between a Central Bank and Commercial Banks. They are:

1. The Central Bank is the apex monetary institution which has been specially empowered to exercise control over the banking system of the country. The Commercial Banks on the contrary is a constituent unit of the banking system.
2. The Central Bank does not operate with a profit motive. The primary aim of the Central Bank is to achieve the objectives of the economic policy of the Government and maximise the public welfare through monetary measures.
3. The Central Bank is generally a State-owned institution, while the Commercial Banks are normally privately owned institutions.
4. The Central Bank does not deal directly with the public. The Commercial Banks, on the
   contrary, directly deal with the public.
5. The Central Bank does not compete with the Commercial Banks. Rather it helps them by acting as the lender of the last resort.
6. The Central Bank is the custodian of the foreign exchange reserves of the country. The Commercial Banks are only the dealers in foreign exchange.
7. The Central Bank has the monopoly of note-issue whereas the Commercial Banks don’t enjoy such right.
8. The Central Bank acts as the banker to the Government, the Commercial Banks act as bankers to the general public.
9. The Central Bank acts as the bankers’ bank :
   • the Commercial Banks are required to keep a certain proportion of their reserve with Central Bank,
   • the Central Bank helps them at the time of emergency,
   • the Central Bank acts as the clearing house for the Commercial Banks. But the Commercial Banks perform to such functions.

Group – C

Objective type Questions with Answers
I. Multiple Choice Questions with Answers :

Question 1.
Which is not treated as function of money?
(i) medium of exchange
(ii) measure of value
(iii) store of value
(iv) all of the above
Answer:
(iv) all of the above

Question 2.
Which is not treated as near money?
(i) cheques
(ii) drafts
(iii) one rupee coin
(iv) bonds
Answer:
(iii) one rupee cQin

Question 3.
Bank drafts are called near money because
(i) it is easily convertible into money
(ii) it has got general acceptability
(iii) it has legal approval
(iv) all of the above
Answer:
(i) it is easily convertible into money

Question 4. Which deposit bears highest rate of interest?
(i) current deposit
(ii) fixed deposit
(iii) saving deposit
(iv) all of the above
Answer:
(ii) fixed deposit

Question 5.
What type of deposit is appreciated by the business man?
(i) fixed deposit
(ii) saving deposit
(iii) deposit made with bonds & securities
(iv) None of these
Answer:
(iii) deposit made with bonds & securities

Question 6.
Which deposit can be withdrawn without prior notice?
(i) saving deposit
(ii) current deposit
(iii) time deposit
(iv) fixed deposit
Answer:
(ii) current deposit

Question 7.
The deposit which does not carry any interest is called
(i) fixed deposit
(ii) current deposit
(iii) saving deposit
(iv) recurring deposit
Answer:
(ii) current deposit

Question 8.
What type of loan is familiar in trade & commerce
(i) direct loan
(ii) over draft
(iii) cash credit
(iv) both (i) and (ii)
Answer:
(iii) cash credit

Question 9.
The system through which a depositor can withdraw more money as loan than its deposit is called
(i) cash credit
(ii) discounting bills of exchange
(iii) overdraft
(iv) direct loan
Answer:
(iii) overdraft

Question 10.
Which is a function of commercial banks?
(i) Remittance of funds
(ii) payments of insurance premium
(iii) locker facility
(iv) all of the above
Answer:
(iv) all of the above

Question 11.
Which is the liability of commercial banks?
(i) time deposit
(ii) paid up capital
(iii) cash in hand
(iv) both (I) and (ii)
Answer:
(iv) both (I) and (ii)

Question 12.
Which is the liability of the commercial banks?
(i) all types of deposits
(ii) authorised.capital
(iii) borrowing from other banks
(iv) all of the above
Answer:
(iv) all of the above

Question 13.
Which is not the asset of the commercial banks
(i) loans & advances
(ii) cash with RBI
(iii) Reserve funds
(iv) investments
Answer:
(iii) Reserve funds

Question 14.
Which is the most liquid asset of the commercial banks?
(i) cash in hand
(ii) saving deposit
(iii) loans and advances
(iv) investments
Answer:
(i) cash in hand

Question 15.
Which is not a function of central bank?
(i) lender of the last resort
(ii) advisor to the govt.
(iii) advances loan to people
(iv) custodian of foreign exchange
Answer:
(iii) advances loan to people

Question 16.
As monopoly of note issue, RBI prints all types of notes except
(i) two rupee notes
(ii) one rupee notes
(iii) five rupee notes
(iv) fifty rupee notes
Answer:
(ii) one rupee notes

Question 17.
Which notes are issued by Ministry of finance?
(i) one rupee notes
(ii) two rupee notes
(iii) five rupee notes
(iv) all of the above
Answer:
(i) one rupee notes

Question 18.
Which bank controls credit?
(i) RBI
(ii) SBI
(iii) Regional rural banks
(iv) all of the above
Answer:
(i) RBI

Question 19.
Which is a method of credit control?
(i) bank rate
(ii) open market operation
(iii) variable cash reserve ratio
(iv) all of the above
Answer:
(iv) all of the above

Question 20.
When Reserve Bank of India increases bank rate, the demand for loan
(i) increases
(ii) decreases
(iii) not affected
(iv) none of the above
Answer:
(ii) decreases

Question 21.
Barteris:
(i) Indirect exchange of goods against goods is called barter
(ii) Direct exchange of goods against goods is called bartar.
(iii) Both (i) and (ii)
(iv) None of the above
Answer:
(ii) Direct exchange of goods against goods is called bartar.

Question 22.
Detinemoeny:
(i) Money is what money does
(ii) Direct exchange of goods against goods in money
(iii) Anything that possesses general acceptability is money
(iv) None of the above
Answer:
(iii) Anything that possesses general acceptability is money

Question 23.
The function of money are:
(i) A medium and a measure
(ii) A standard and a store
(iii) Both (I) and (ii)
(iv) None of the above
Answer:
(iii) Both (i) and (ii)

Question 24.
Moneyservesasalinicbetween:
(i) The present and past
(ii) The past and future :
(iii) The present and future
(iv) None of the above
Answer:
(iii) The present and future

Question 25.
Moeny facilities:
(i) Barter transaction
(ii) credit transaction
(iii) All of the above
(iv) None of the above
Answer:
(ii) credit transaction.

Question 26.
Example of near money is:
(i) Time or fixed deposits
(ii) BillS of exchange and Treasury bill
(iii) Stock and share
(iv) All of the above
Answer:
(i) All of the above :

Question 27.
A command Bank has:
(i) Unlimited credit creation power
(ii) Limited credit creation power
(iii) All of the above
(iv) None of the above
Answer:
(ii) Limited credit creation power

Question 28.
Primary function of a commercial bank is:
(i) To finance Internal and External trade
(ii) Creation of moeny
(iii) Acceptance of deposits
(iv) None of the above
Answer:
(iii) Acceptance of deposits

Question 29.
The right-hand side of the balance sheet shows the items under the:
(i) Liabilities
(ii) Assets
(iii) Cash
(iv) None of the above
Answer:
(ii) Assets.

Question 30.
Cash-in-hand is otherwise known as:
(i) Till money
(ii) Cash-rn-vault
(iii) Both (i) and (ii)
(iv) None of the above
Answer:
(iii) Both (j) and (ii)

Question 31.
Moeny at call and short-notice is a:
(i) Long period loans
(ii) Very short term loans
(iii) Both (j) and (ii)
(iv) None of the above
Answer:
(i) Very short term loans

Question 32.
One rupee not is issued by:
(i) R. B. I
(ii) Commercial Bank
(iii) Govt. of India
(iv) None of the above
Answer:
(iii) Govt. of India

Question 33.
Time deposits are withdrawn:
(i) On the demand
(ii) After the expiry of the period
(iii) All of the above
(iv) None of the above
Answer:
(i) After the expiry of the period

Question 34.
Most liquid asset of a commercial bank is:
(i) Demand deposits
(ii) Investment
(iii) Cash
(iv) None of the above
Answer:
(iii) Cash

Question 35.
Under which principle the central Bank of India issues notes:
(i) Proportional reserve system
(ii) Minimum reserve system
(iii) Maximum reserve system
(iv) None of the above
Answer:
(ii) Minimum reserve system

Question 36.
Quantitative credit control method refers to:
(i) Control the use of credit
(ii) Bring change in the total volume of credit in general
(iii) All of the above
(iv) None of the above
Answer:
(ii) Bring change in the total volume of credit in general

Question 37.
The selective credit control methods adopted by the central Bank to control credit are:
(i) Open market operation
(ii) Regulation of margin-requrements
(iii) Regulation on of consumers credit
(iv) Both (ii) and (iii)
Answer:
(i) Both (ii) and (iii)

Question 38.
The function of central Bank:
(i) Lender of the lust resort
(ii) Clearing agent
(iii) Banker’s Bank
(iv) All of the above
Answer:
(iv) All of the above

Question 39.
Central Bank acts as a financial advisor to the:
(i) General public
(ii) Commercial Banks
(iii) Govt.
(iv) None of the above
Answer:
(iii) Govt.

II. Fill in the blanks :

Question 1.
Money acts as a ______ of account.
Answer:
unit

Question 2.
Money acts as a ______ it facilitates credit transaction.
Answer:
standard of deferred payment

Question 3.
Near money is less liquid than ______.
Answer:
money proper.

Question 4.
Travellers’ cheque is an example of ______.
Answer:
Near money.

Question 5.
Postal savings deposits are examples of ______.
Answer:
Near-money.

Question 6.
______ deposit can be withdrawn at any moment.
Answer:
Current

Question 7.
______ deposit does not bear any interest.
Answer:
Current

Question 8.
______ Bank aims at the attainment of objectives of economic policy.
Answer:
Central

Question 9.
______ deposit carries the highest interest.
Answer:
Fixed

Question 10.
______ loans are very long period loAnswer:
Answer:
Term

Question 11.
______ Bank creates credit.
Answer:
Commercial

Question 12.
Through ______ system, the depositor can withdraw the amount in excess of his deposits.
Answer:
overdraft

Question 13.
______ Banks operate with a profit motive.
Answer:
Commercial

Question 14.
______ Bank controls credit.
Answer:
Central

Question 15.
______ Bank has got a large number of branches all over the country.
Answer:
Commercial

Question 16.
______ Bank acts as a banker to the Government.
Answer:
Central

Question 17.
______ Bank acts as a financial advisor to the Government.
Answer:
Central

Question 18.
______ Banks act as clearing agent.
Answer:
Central

Question 19.
______ Bank is the lender of the last resort.
Answer:
Central

Question 20.
______ is the primary function of the money.
Answer:
Medium of exchange

Question 21.
______ Bank draft is a Money.
Answer:
Near

Question 22.
______ deposit is called demand deposit.
Answer:
Current

Question 23.
______ deposit is appreciated by the business man.
Answer:
Current

Question 24.
______ deposit can be withdrawn at any moment without any notice.
Answer:
Current

Question 25.
______ deposit is kept for a particular period.
Answer:
Fixed

Question 26.
______ circulates one rupee note
Answer:
Ministry of Finance Govt, of India

Question 27.
______ Signs on the Hundred rappee note.
Answer:
Governor of Reserve Bank of India

Question 28.
______ is the Central Bank of India
Answer:
RBI

Question 29.
______ Bank formulate economic policy in India.
Answer:
RBI

Question 30.
Cheque is ______ Money
Answer:
Near

III. Correct the Sentences:

Question 1.
Money acting as a medium of exchange is known as unit of account.
Answer:
Incorrect.
Correct – Money acting as a measure of value is known as unit of account.

Question 2.
Money discourages specialisation.
Answer:
Incorrect.
Correct – Money encourages specialisation.

Question 3.
Money acting as a measure value keeps a link between present & future.
Answer:
Incorrect.
Correct – Money acting as a store of value keeps a link between present & future.

Question 4.
Money acting as measure of value facilitates credit transaction.
Answer:
Incorrect.
Correct – Money acting as a standard of deferred payment facilitates credit transaction.

Question 5.
Store of value is a primary function of money.
Answer:
Incorrect.
Correct – Store of value is a secondary function of money.

Question 6.
Near money is more liquid than money itself. .
Answer:
Incorrect.
Correct – Money is more liquid than near money.

Question 7.
Near money can be easily convertible into money.
Answer:
Correct.

Question 8.
Postal saving is near money.
Answer:
Correct.

Question 9.
Current deposit is money itself.
Answer:
Incorrect.
Correct – Current deposit is a near money.

Question 10.
Treasury bill is money.
Answer:
Incorrect.
Correct – Treasury bill is near money.

Question 11.
Fixed deposit is more popular among businessmen.
Answer:
Incorrect.
Correct – Current deposit is more popular among businessmen.

Question 12.
Current deposit bears higher rate of interest.
Answer: Incorrect.
Correct – Current deposit bears no interest.

Question 13.
Saving deposit bears the highest rate of interest.
Answer:
Incorrect.
Correct – Fixed deposit bears the highest rate of interest.

Question 14.
Central bank creates credit.
Answer:
Incorrect.
Correct – Commercial bank creates credit.

Question 15.
Deposits are the most liquid asset of the bank.
Answer:
Incorrect.
Correct – Cash in hand is the most liquid asset of the bank.

Question 16.
Deposits are the assets of the bank.
Answer:
Incorrect.
Correct – Deposits are the liability of the bank.

Question 17.
Loans & advances are the liabilities of the bank.
Answer:
Incorrect.
Correct – Loans & advances are the assets of the bank.

Question 18.
Commercial banks stand at the apex of the banking system.
Answer:
Incorrect.
Correct – Central bank stands at the apex of the banking system.

Question 19.
There are many Central banks in a countries.
Answer:
Incorrect.
Correct – There is a Central bank in a country.

Question 20.
Commercial bank controls credit.
Answer:
Incorrect.
Correct – Central bank controls credit.

Question 21.
Central bank is bankers bank.
Answer:
Correct.

Question 22.
Central bank issues one-rupee note.
Answer:
Incorrect.
Correct – Secretary, Ministry of finance issues one-rupee note.

Question 23.
Commercial bank is the lender of the last resort.
Answer:
Incorrect.
Correct – Central bank is the lender of the last resort.

Question 24.
Commercial bank is the custodian of cash reserve.
Answer:
Incorrect.
Correct – Central bank is the custodian of cash reserve.

Question 25.
Time deposits are withdrawn on demand.
Answer:
Incorrect.
Correct – Demand deposits are withdrawn on demand.

Question 26.
Central bank is profit motivated.
Answer:
Incorrect.
Correct – Commercial bank is profit motivated.

Question 27.
India follows branch banking system.
Answer:
Correct.

IV. Answer the following questions in one word :

Question 1.
What is money?
Answer:
Anything which is universally accepted a medium of exchange, measure of values, standard of deferred payment & store of values is called money.

Question 2.
What is primary function of money ?
Answer:
“Money acts as a medium of exchange” is the primary function of money.

Question 3.
What is a secondary function of money?
Answer:
“Money acts as a store of value” is called secondary function of money.

Question 4.
What is near money?
Answer:
Near money refers to the liquid assets which can be easily convertible into money.

Question 5.
Give on example of near money.
Answer:
Bills of exchange is an example of near money.

Question 6.
What is deferred payment?
Answer:
The payment not made at present but made in future for current transaction is called deferred payment.

Question 7.
Who defined money as “Money is what money does”?
Answer:
Prof. Francis Walker.

Question 8.
Which function of money facilitates purchase of goods?
Answer:
Money acting as medium of exchange facilitates the purchase of goods.

Question 9.
Which function of money treats it as a unit of account?
Answer:
When money acts as a measure of value, it is known as unit of account.

Question 10.
Which function of money shows it as a link between present?
Answer:
Money acting as a store of value signifies it as a link between present & future.

Question 11.
Which function of money signifies its role in credit transaction ?
Answer:
The function like “Standard of deferred payment, signifies its role in credit transactions.

Question 12.
Write one contingent function of money.
Answer:
Money is a basis of credit system.

Question 13.
Give an example of near money.
Answer:
Treasury bills of Bank Draft or Cheque or Bond is the example of near money.

Question 14.
What is bank money?
Answer:
Bank deposit is the bank money.

Question 15.
What is commercial bank?
Answer:
Commercial bank is a financial institution which collects deposits from the people, gives loan & creates credit.

Question 16.
Define Commercial bank?
Answer:
Commercial bank is an institution whose debts (bank deposits) are widely accepted in settlement of other people’s debts to each other.

Question 17.
Write an instrument of a bank through which claim of the depositor is transferred?
Answer:
Cheques.

Question 18.
From which term “Bank” has been derived?
Answer:
The term ‘bank’ has been derived from the German word Bank which means bench.

Question 19.
What is current deposit?
Answer:
The deposit which can be withdrawn on any day during the working hours of the bank is called current deposit.

Question 20.
What is fixed deposit?
Answer:
The deposit which can not be withdrawn before the expiry of the period of maturity is called fixed deposit.

Question 21.
Which deposit earns the highest rate of interest?
Answer:
Fixed deposit earns the highest rate of interest.

Question 22.
For which deposit no interest is paid?
Answer:
Current deposit

Question 23.
Which banks create credit?
Answer:
Commercial banks create credit.

Question 24.
Which deposit is called demand deposit?
Answer:
Current deposit is called demand depsit.

Question 25.
Which deposit is more popular among the traders?
Answer:
Demand or current deposit is more popular among the traders.

Question 26.
What is cash credit?
Answer:
Cash credit is a system adopted by the commercial banks to advance loans in which borrower can avail loans by opening a current
account in his name.

Question 27.
What is overdraft system?
Answer:
Overdraft system is a method of advancing loans in which the depositor of a bank can withdraw the amount in excess of its deposit made.

Question 28.
Which banks create credit?
Answer:
Commercial banks create credit.

Question 29.
What are the bank instruments through which funds can be remitted?
Answer:
Cheques & Drafts.

Question 30.
What is balance sheet?
Answer:
Balance sheet is a systematic record of a commercial banks showing its assets & liabilities during a particular financial year.

Question 31.
Which is the most liquid asset of the bank?
Answer:
Cash in hand is the most liquid asset of the bank.

Question 32.
Which bank is at the apex of banking system?
Answer:
Central bank.

Question 33.
Which bank is called bankers bank?
Answer:
Central bank.

Question 34.
Which bank is called bank of issue?
Answer:
Central bank.

Question 35.
Which bank controls credit?
Answer:
Central bank.

Question 36.
Which bank issues notes?
Answer:
Central banks.

Question 37.
Which bank is called the lender of the last resort?
Answer:
Central bank.

Question 38.
Which bank issues two-rupee notes?
Answer:
Central bank.

Question 39.
Who does issue One-rupee note in India.
Answer:
Secretary, Ministry of Fianance.

Question 40.
What is the name of the central bank in India?
Answer:
Reserve Bank of India.

Odisha State Board CHSE Odisha Class 12 Economics Solutions Chapter 11 Theory of Income Determination Questions and Answers.

CHSE Odisha 12th Class Economics Chapter 10 Question Answer Theory of Income Determination

Group – A

Short type Questions with Answers
I. Answer with in Two/Three sentence.

Justify the statement:
Question 1.
In full employment, Aggregate Demand (AD) = Aggregate supply (AS).
Answer:
In full employment all the existing resources sum to be fully employed & hence total expenditure in final goods & services at given lenel of employment becomes equal to aggregate supply (CAS) So, in full employment, AD = AS,

Question 2.
Full employment is an Imaginary concept.
Answer:
Full employment is a situation in all resources are employed. But in this situation, there may be frictional, structural second & above all voluntary unemployment. So it is an imaginary concept.

Question 3.
Excess demand leads to inflation.
Answer:
Excess demand arises when total expenditure on goods & services (AD) exceeds the value of aggregate supply of goods & services (AS). So, it leads to inflation.

Question 4.
Deficient demand leads to depression.
Answer:
When aggregate demand for goods & services in the economy falls short of available aggregate supply (AS), it causes deficient demand. This leads to depression.

Question 5.
Full employment is an imaginary concept?
Answer:
Full employment is a situation in which there is no involuntary unemployment though there may be frictional, sturucture or voluntary unemployment, so the concept of the full employment is practically an absurd concept.

Question 6.
Under employment is very much visible in UDCs.
Answer:
In UDCs, the persons who seem to be employed are not properly placed according to their qualification, skill experience. Besides, most of the people don’t get the job throughout the year, hence underemployment is quite visible in UDCs.

Question 7.
Aggregate demand curve slopes upward.
Answer:
Aggregate demand represents total expenditure spent on final goods and. services which increases with the increase in employment level/ income. As aggregate demand curve reveals the relationship between employment and total expenditure on final goods (C +1 + G), it slopes upward.

Question 8.
Effective demand is normally desirable.
Answer:
The demand at which AD = AS it is called effective demand and it tells about the equilibrium situation in the economy. Besides, it does not reult any economic crisis for which it is normally desirable.

Question 9.
Excess aggregate demand leads to inflation.
Answer:
If AD > AS, it indicates that the total expenditure on final goods and services exceeds the value of total goods available in the economy during a particular time. In this case, investment exceeds consumption which leads to inflation.

Question 10.
Deficient aggregate demand leads to deflation.
Answer:
In deficient aggregate demand AD < AS i.e., total expenditure on final goods & service is less than the available supply. Here, saving exceeds investment and it leads to deflation.

Question 11.
Consumption can never be zero ? .
Answer:
Consumption increases with the increase in income though consumption does not increase to the extent of increase in income. If income is zero consumption shall not be zero as the consumer can spend out of his past saving, borrowing etc.

II. Answer with in Five/Six sentence :

Write Short Notes on :
Question 1.
Agregate demand.
Answer:
Indirect tax is that tax the burden of which can be shifted or transferred from one to other. This tax is legally imposed on a person who actually does not bear the ultimate burden of such tax. Rather, he is able to shift this burden to other persons who are not aware of such tax. In economic term, the impact & incidence of such tax fall on different person. Sales tax is an example of such tax.

Question 2.
Aggregate supply
Answer:
Aggregate supply is reflected by the total volume of national product produced in the country at a given level of employment. In other words, it refers to the flow of total volume of goods & services during a particular period. It is also the aggregate cost of production which goes to the factors of production by the way of rent, wage interest & profit. It is assessed as the sum of consumption & saving.

Question 3.
Full Employment equilibrium.
Answer:
The level of equilibrium is attained at the point of interaction between aggregate demand and aggregate supply. There are three possible situations where equilibrium may be established. It may be at the level of more than full employment or less, than full employment or at full employment. Full employment refers to a situation where all the available resources get employed and production is maximum. This is an ideal situation.

Question 4.
Excess demand.
Answer:
(i) Excess demand refers to a demand condition over and above the output available under full employment condition of the economy.
(ii) In this situation aggregate demand is more than aggregate supply.
(iii) Excess demand leads to emergence of inflationary gap in the economy.
(iv) Excess demand gives rise to price rise in the economy

Question 5.
Deficit demand.
Answer:
(i) Deficit demand refers to a situation below the level of output available at full employment equilibrium.
(ii) Aggregate supply remains higher than aggregate demand.
(iii) It generates deflationary gap in the economy.
(iv) Deficit demand leads to fall in price out put and employment

Justify the following statement:

Question 6.
The Keynesian theory of income and employment ignores aggregate supply function.
Answer:
The aggregate supply function in an economy is influenced by utilisation of available resources and state of technology. The resource base cannot be increased or decreased in the short period, so also the technical production condition. State of technology influences the productivity of man, material and machines. State of technology cannot be altered in the short period. Hence, the aggregate supply function is assumed to be constant in the short period. So in Keynesian analysis of income and employment determination the aggregate supply function has been ignored.

Question 7.
The Keynesian theory of employment is based upon rejection of the Say’s law of market.
Answer:
The classical economists, basing upon the Say’s law of market, i.e. supply creates its own demand, were of firm view that the economy tends to be in the level of full employment and if there is any disequilibrium it is automatically adjusted. Keynes rejected the classical contention. He maintained that a situation of full-employment is rarely found. There always exists involuntary unemployment because equality between aggregate demand and aggregate supply doesn’t always clear the labour market. Aggregate demand falls short of aggregate supply. Investment is not equal to savings. So there is deficiency of demand.

Question 8.
Aggregate demand function determines the level of employment and output.
Answer:
The aggregate demand function comprises (1) Private consumption expenditure, (2) Private investment expenditure, (3) Public investment, and (4) Net export. Consumption expenditure has a tendency to lag behind income. Since consumption increases less than income, the gap between income and expenditure widens as income grows. In order to maintain aggregate demand at a desired level it is necessary to increase investment. Since aggregate supply is taken to be fixed in the short period, aggregate demand is said to determine the level of employment and income.

Question 9.
Different aggregate demands are associated with different levels of output.
Answer:
The other name of aggregate demand is effective demand. The aggregate demand represents a flow of monetary expenditure on final goods and services produced during a given period. It is the total money receipts that the producers expect to get by selling the output produced at a particular level of employment. Hence, it is said that, different aggregate demands are associated with different levels of output.

Question 10.
Marginal propensity to consume is more in case of the poor as compared to the rich.
Answer:
Marginal propensity to consume is the rate of change in consumption to change in income. As income increases consumption increases but less than proportionately. The propensity to consume in case of the rich is low, but it is high in case of the poor. This is because the poor having low income cannot profit all their demand. As income is redistributed in favour of the poor their income increases and their consumption expenditure also increases in order to fulfil their demand.

Question 11.
Assumption of full employment condition in the economy is illusive.
Answer:
The assumption of full employment is illusive as all that is produced is not sold in the market nor all income is converted into expenditure. There does not prevail form competition in the product market and factor market. All that is saved is not invested. As a result aggregate demand falls short of aggregate supply and there is over production and involuntary unemployment. Hence, full employment condition in the economy is illusive.

Question 12.
The remedy for unemployment can be found in a flexible wage and price system.
Answer:
The classical economists ruled out the possibility of persistent unemployment in the economy. However, if there will be temporary unemployment it can be corrected, as asserted by Pigou, by following a flexible wage and price policy. Prof Pigou maintained that a temporary unemployment situation can be remedied by following a policy of wage cut. It would be possible if workers are made to accept lower wages. A wage cut will reduce the supply of labour and increase the demand for labour. Constantly supply of labour will be equal to demand for labour. Unemployment will thus disappear. But this is not possible as pointed out by Keynes. A wage cut while reducing costs also reduces income apd purchasing power which creates unemployment due to reduction in effective demand.

(B) Distinguish Between

Question 13.
Aggregate Demand & Aggregate Supply.
Answer:
(a) Aggregate demand refers to the total amount of expenditure spent on final goods & services at a given level of employment whereas aggregate supply refers to the total volume of goods & services supplied at a given level of employment.

(b) Aggregate demand is the maximum quantity of goods & services at a given level of
employment whereas aggregate supply is the minimum sale proceeds expected at a given level of employment.

(c) Aggregate demand is composed of consumption demand & Investment demand. On the other hand, aggregate supply is composed of consumption & saving.

Question 14.
Full employment equilibrium & Underemployment equilibrium.
Answer:
The level of equilibrium is attained at the point of interaction between aggregate demand and aggregate supply. There are three possible situations where equilibrium may be established. It may be at the level of more than full employment or less than full employment or at full employment. Full employment refers to a situation where all the available resources get employed and production is maximum, This is an ideal situation.

Under-employment equilibrium refers to a situation when available supply of goods equal to the demand but resources remain unutilised in the economy. There is excess capacity in plants and industries. This situation of equilibrium is struck not due to low level of aggregate supply but due to the low level of aggregate demand.

Question 15.
Excess demand & Deficit Demand.
Answer:
Excess demand :

1. Excess demand refers to a demand condition over and above the output available under full employment condition of the economy.
2. In this situation aggregate demand is more than aggregate supply.
3. Excess demand leads to emergence of inflationary gap in the economy.
4. Excess demand gives rise to price rise inthe economy Deficit demand:
5. Deficit demand refers to a situation below the level of output available at full employment equilibrium.
6. Aggregate supply remains higher than aggregate demand
7. It generates deflationary gap in the economy
8. Deficit demand leads to fall in price out put and employment

Group – B

Long Type Questions With Answers

Question 1.
Explain the concept of aggregate demand and aggregate supply.
Answer:
A discussion of aggregate demand and aggregate supply is relevant in the context of determination of employment and output as discussed by Keynes. According to Keynes a situation of full employment rarely comes about as aggregate demand falls short of aggregate supply. In such a situation the unemployment which arises due to deficient demand is described as involuntary unemployment. In a situation of involuntary unemployment people willing to work at current rate of wages do not find employment.

Aggregate demand – Aggregate demand or aggregate expenditure refers to total expenditure on goods and services during a year. Demand for goods and services may be for consumption, investment and net export. Consumption demand may be divided as private consumption demand and public consumption demand. Investment demand may arise from private sources and public sources. Aggregate demand depends upon level of employment and there is a direct and positive relationship between them. Aggregate demand consists of (a) Household consumption demand (b) Investment demand, (c) Government demand for goods and services, and (d) Net export demand. These elements may be discussed as under.

(a) Households’ consumption demand – Household consumption depends upon the income of the household. A house- hold pays personal taxes from its income and the remainder known as disposable income, is devoted for consumption. The relationship between disposable income and consumption is called consumption function or propensity to consume. As one’s income increases consumption increases but less than proportionately often subsistence level. Consumption function, according to Keynes, plays an important role in determination of employment. Employment depends upon effective demand and effective demand depends on consumption functions. The relationship between consumption and income is expressed in the formula C – f(Y). C stands for consumption and Y stands for income. This formula suggests that a change in income is followed by a change in consumption.

(b) Investment demand – Investment refers to that part of savings which is used for production of capital goods. All that is saved in all economy does not flow into investment channels. Investment involves risk. People want their hard earned saving to be safe in the hands of investors. Since people part with their savings they face inconvenience. So they must seek to be compensated for the risk and inconvenience they face. If investors get more return than what they sacrifice, then they can adequately compensate the savers. The return on invest expressed as a percentage of investment is termed marginal efficiency of capital. It may be defined as the expected rate of interest on all additional units of capital goods. There is an inverse relationship between rate of interest and investment demand. In other words, at higher rates of interest investment demand will be less and vice versa. The curve representing marginal efficiency of capital is therefore downward sloping.

(c) Government demand for goods and services – Like private consumption demand of households and firms, goods and services are demanded by the government for the institutions run by it. The policy and practices of the government determine the quantum of demand.

(d) Net exports demand – The difference between exports and imports represents the net exports. Net exports depend on foreign demand for domestic goods and services. Foreign demand is influenced by the foreign exchange policies of the trading countries, relative price of goods, political relations between trading countries etc.

The aggregate demand can be represented diagrammatically as follows.

In the diagram employment is shown on OX axis and aggregate demand on the OY oxis. The aggregate demand function, ADF intercepts the Y axis a point P, implying that even at zero level of output and employment there is some amount of aggregate demand present in the economy. The aggregate demand which consists of all the components cited above is nothing but the proceeds expected by the entrepreneurs in the economy.

To sum up AD = C +1 + G + (x-m) = ED = Y
C – Stands for consumption expenditure
I – Stands for investment expenditure
G – Stands for government expenditure
(x-m) – Stands for net exports (exports-imports)
ED – Stands for effective demand
Y – Stands for national income.

Aggregate supply : Aggregate supply consists of goods and services produced in the economy during a year, by individuals, firms and the government. The net national products represent the aggregate supply. It is the aggregate cost of producing goods. It represents the minimum sale proceeds which the producers get. The sale proceeds constitute the income of the producers which they pay to factors as rent, wage, interest, profit. Income, thus generated is either consumed or saved.

Consumption and savings are the two constituents of income. This can be expressed as AS = C + S. Aggregate supply is influenced by additional utilisation of resources and technological improvement. Technology cannot be charged in the short period. Increase in aggregate supply is possible only through additional use of resources. So long as resources are not fully employed it is possible to increase supply of goods and services in proportion to employment of resources and vice versa.

This relationship can be expressed diagrammatically as follows :

In the along side diagram the aggregate supply function is represented by AS line which starts from origin.-It shows that aggregate supply in the economy increases as employment increases. After full employment level is reached, the ASF becomes perfectly inelastic.

Question 2.
How is the equilibrium level of income determined in the economy?
Answer:
The theory of income determination forms an integral part of macro-economics. J. M. Keynes, a prominent British economists propounded this principle in his book “General Theory of Employment, Interest & Money. “According to Keynes, the level of income & employment in an economy depend on the “effective demand”. The effective demand is an integral part of the theory which consists of interaction of the two determines the effective demand as well as the equilibrium level of income.

Aggregate demand: Aggregate demand refers to the total expenditure incurred on goods & services produced in the economy at a given level of employment. It consists of household consumption demand, private investment demand, government demand & net export demand. The sum of all these components give rise to aggregate demand.

Total Household consumption demand includes the demand for goods & services made by the household for consumption purposes. This depends on the level of disposable income of the households. Similarly, the investment demand which is made for the creation of capital goods or for further production becomes another part of aggregate demand. The demand made by the government for the satisfaction of collective needs is also another part. Lastly, the net export net income from abroad (X-m) is added to all the above to have aggregate demand.

Thus AD = C + I + G + (X – M)
This aggregate demand is the function of income or employment, i.e., AD = f (N). With the increase in income or employment, the aggregate demand increases & vice-versa. This nation is described in the following aggregate demand schedule.

Aggregate Demand Schedule

Income	Employment
0	20
10	25
20	30
30	35
40	40
50	45

Aggregate Supply : Aggregate supply indicates the flow of final goods & services during a . particular period at a given level of employment. It includes aggregate cost of producing the output which forms the income of the factors. Thus, the aggregate supply (AS) or the national income (Y) is the sum of consumption (C) & saving (S) that is,
AS = C + S.
Like AD, AS also depends on the level of income. There is direct relationship between the AS & level of income. The same is expressed in the following schedule.

Aggregate Supply Schedule

Income	Employment
0	0
10	10
20	20
30	30
40	40
50	50

This schedule reveals the proportionate relationship between aggregate supply & level of employment or income.

Equilibrium Level of Income:
Equilibrium level of income can be determined with the interaction of aggregate demand and aggregate supply. It is determined at a point where aggregate demand is equal to aggregate supply. This point also indicates “Effective demand”.

According to this,
AD = AS
⇒ C + J = C + S
⇒ I = S

The equilibrium level of income can also be determined at a point where saving in the economy is equal to investment as presented in the above equation.

According to Keynes, effective demand is the sole determinant of income & employment. In other words, the equality between AD & AS determines the equilibrium level of income. This concept is numerically & graphically illustrated below :

Numerical Analysis:

Level of Employment (in thouseands)	Aggregate Demand (in crores)	Aggregate Supply in crores)
0	20	0
10	25	10
20	30	20
30	35	30
40	40	40
50	45	50
60	50	60

In the above table, equilibrium is revealed when 40,000 workers are employed. Because at this level of employment or income, AD = AS = 40 crore so the income arising from there 40,000 workers is found to be equilibrium level of income.

Graphical Analysis: The figure measures income on OX-axis & consumption & investment on OY-axis. The aggregate supply curve (AS) is a straight line drawn from the origin with 45° angle.

Line AD (C+I) reflects the aggregate demand curve.

Both the lines intersects at point E resulting equilibrum level of income. E also reveals the point of effective demand corresponding to this point (E), OY – level of income is determined which is the equilibrium level of income.

Question 3.
Explain the concept of excess deihand & deficit demand with the help of diagram.
Answer:
Deficit demand and excess demand are two terms which are frequently used in any discussion on Keyne’s theory of employment and income. According to Keynes it is the aggregate demand or effective demand which determines the level of employment and the equality between aggregate demand and aggregate supply determines the equilibrium level of employment. With regard to equilibrium three situations can be visualised viz. full employment equilibrium, less than full employment equilibrium and more than full employment equilibrium.

At the level of full employment equilibrium aggregate demand is equal to aggregate supply. At this situation all resources fully utilised and all able bodied persons willing to work at the prevailing rate of wages get employment. Otherwise there will be involuntary unemployment. This is due to inadequacy of demand which is otherwise called deficit demand.

Deficit demand: Deficit demand refers to a situation where aggregate demand falls short of aggregate supply corresponding to the level of full employment. The short fall in the aggregate demand from the level of full employment equilibrium is called the deflationary gap. The case of deficit demand is shown in the following diagram :

In the diagram ON represents full employment level of output. AD represent the aggregate demand and AS represents the aggregate supply. Intersection of AD and AS and ‘E’ suggests the income at full employment equilibrium. If the level of income shifts to OM the aggregate demand becomes SM and the aggregate supply becomes EN. Excess of AS over AD at full employment indicates deficit demand or deflationary gap. A deficit demand situation arises when the total demand for goods and services is not sufficient enough to ensure the buying of the existing supply of goods coming to the market at the prevailing prices. Deflation is caused by a shortage of aggregate demand relative to the total supply at given prices. Shortage in aggregate demand may be the result of either a decline in private investment or a fall in government spending or a decrease in consumption expenditure.

Excess demand : After the stage of full employment when resources are fully utilised and there is no idle resources output and employment cannot increase in response to increase in demand. This situation is described as excess demand. This situation of excess demand may be studied with the help of following diagram:

The diagram shows that OR is the level of income at full employment, the AD and AS being equal ‘E’ the equilibrium point. If the full employment position shifts to OQ the AD becomes QT and AS become SQ. Here the aggregate demand exceeds aggregate supply by TS. TS represents the degree of excess demand of extent of inflationary gap. At this situation there will be a tendency for money income prices to increase.

Group – C

Objective type Questions with Answers
I. Multiple Choice Questions with Answers :

Question 1.
Total expenditure on goods & services during a year is known as
(i) total demand
(ii) aggregate demand
(iii) Aggregate supply
(iv) all of the above
Answer:
(ii) aggregate demand

Question 2.
Aggregate demand cosists of
(i) consumption demand
(ii) investment demand
(iii) Govt, demand
(iv) all of the above
Answer:
(iv) all of the above

Question 3.
Which is not the component of aggregate demand?
(i) consumption demand
(ii) investment demand
(iii) saving
(iv) net export
Answer:
(iii) saving

Question 4.
Goods & services produced in the economy during a year indicates
(i) aggregate demand
(ii) aggregate supply
(iii) total supply
(iv) all of the above
Answer:
(ii) aggregate supply

Question 5.
Which is the component of aggregate supply?
(i) consumption
(ii) saving
(iii) investment
(iv) both (i) and (ii)
Answer:
(iv) both (i) and (ii)

Question 6.
Equilibrium level of income is determined by
(i) aggregate demand
(ii) Aggregate supply
(iii) income of the household
(iv) Both (i) and (ii)
Answer:
(iv) Both (i) and (ii)

Question 7.
Equilibrium level of income is determined at the point where
(i) AD = AS
(ii) AD > AS
(iii) AD < AS
(iv) None of the above
Answer:
(i) AD = AS

Question 8.
Full employment is a situation in which AD is equal to
(i) AS
(ii) saving
(iii) investment
(iv) all of the above

Question 9.
It the AD > AS at full employment the effect shows
(i) increase in output
(ii) increase in national income
(iii) increase in price
(iv) all of the above

Question 10.
If AD > AS, the price-level will
(i) rise
(ii) fall
(iii) remains constant
(iv) none of the above
Answer:
(iv) all of the above

Question 11.
If AD > AS, the employment will
(i) increase
(ii) decrease
(iii) remains unchanged
(iv) Both (i) and (ii)
Answer:
(i) increase

Question 12.
If there is deficit demand, the effect on economy is .
(i) fall in price
(ii) fall in output
(iii) fall in employment
(iv) all of the above
Answer:
(iv) all of the above

Question 13.
If AD < AS at full employment, the result is ,
(i) unemployment
(ii) under employment
(iii) excess employment
(iv) disguised employment ,
Answer:
(i) unemployment

Question 14.
It available supply of goods becomes equal to demand but some resources remain unutilised, it is a case of
(i) unemployment
(ii) under employment equilibrium
(iii) full employment equilibrium
(iv) none of the above
Answer:
(ii) under employment equilibrium

Question 15.
The under employment equilibrium results some unutilised resources, but the demand for goods becomes
(i) greater than available supply
(ii) less than available supply
(iii) equal to available supply
(iv) Both (i) and (ii)
Answer:
(iii) equal to available supply

Question 16.
Which is not the outcome of excess demand?
(i) inflation
(ii) deflation
(iii) unequal distribution of income
(iv) Both (i) and (ii)
Answer:
(ii) deflation

Question 17.
Which is not the result of deficit demand?
(i) Inflation
(ii) deflation
(iii) fall in profit
(iv) fall in national income
Answer:
(i) Inflation

Question 18.
Unemployment results due to
(i) inflation
(ii) excess demand
(iii) deficit demand
(iv) Both (i) and (ii)
Answer:
(iii) deficit demand

Question 19.
The General Theory of Employment, Interest and Money of J.M Keynes was published in the year:
(i) 1930
(ii) 1940
(iii) 1936
(iv) 1947
Answer:
(iii) 1936

Question 20.
The Keynesian theory of employment is concerned with involuntary unemployment arising in the economy in the :
(i) Long period
(ii) Short period
(iii) Both (i) and (ii)
(iv) None of the above.
Answer:
(ii) Short period.

Question 21.
Saving and investment are brought to equality through manipulation of:
(i) Rate of interest
(ii) Saving
(iii) Income
(iv) None of the above.
Answer:
(iii) Income

Question 22.
The Marginal propensity to consume is :
(i) Equal to one
(ii) More than one
(iii) Less than one
(iv) None of the above
Answer:
(iii) Less than are

Question 23.
The propensity to consume in case of the rich is :
(i) High
(ii) Less
(iii) One
(iv) None of the above.
Answer:
(ii) Less.

Question 24.
The volume of output and employment in an economy is determined by :
(i) Saving
(ii) Income
(iii) Investment
(iv) All of the above.
Answer:
(iii) Investment

Question 25.
As income increases consumption increases and saving :
(i) Increases
(ii) Decreases
(iii) Remains the same
(iv) None of the above.
Answer:
(i) Increases

Question 26.
Effective demand includes:
(i) Consumption demand
(ii) Investment demand
(iii) Both (1) and (ii)
(iv) None of the above.
Answer:
(iii) Both (j) and (ii)

Question 27.
At the point of equilibrium :
(i) AD > AS
(ii) AD < AS
(iii) AD = AS
(iv) None of the above
Answer:
(iii) AD = AS

Question 28.
Consumption and income are
(i) Inversely related
(ii) Directly related
(iii) Not related
(iv) None of the above
Answer:
(ii) Directly related.

Question 29.
Aggregate demand is a:
(i) Decreasing function of income
(ii) Increasing function of income
(iii) Increasing function of saving
(iv) None of the above.
Answer:
(ii) Increasing function of income.

Question 30.
Investment is the function of .
(i) Income
(ii) Rate of interest
(iii) Saving
(iv) None of the above
Answer:
(ii) Rate of interest.

II. Fill in the blanks:

Question 1.
_____ brings about equality between saving and investment.
Answer:
The income

Question 2.
_____ determines the volume of output and employment in an economy.
Answer:
Investment

Question 3.
Consumption and saving both _____ with increase in income.
Answer:
increase

Question 4.
_____ is income elastic.
Answer:
Investment

Question 5.
_____ demand includes both Consumption Demand and Investment Demand.
Answer:
Effective

Question 6.
If income increases consumption expenditure increases but less than the _____ in income.
Answer:
increase ;

Question 7.
If the _____ increases, the aggregate supply increases in the same proportion.
Answer:
level of employment

Question 8.
At the point of equilibrium, AD = _____
Answer:
AS.

Question 9.
If AD = AS, the _____ must be equal to investment.
Answer:
Saving

Question 10.
Investment is the function of _____
Answer:
Rate of interest.

Question 11.
Equilibrium level of income is determined at the point where saving is equal to _____
Answer:
Investment

Question 12.
Aggregate demand is a _____ function of income.
Answer:
increasing

Question 13.
Consumption and income are _____ related.
Answer:
directly

Question 14.
The theory of income determination is propounded by _____.
Answer:
JM Keynes

Question 15.
Aggregate demand and aggregate supply are two components of _____ demand.
Answer:
Affective

Question 16.
The equilibrium level of income depends on _____.
Answer:
Effective demand

Question 17.
The consumption and saving are the two components of _____.
Answer:
Aggregate supply

Question 18.
The consumption and investment are the two components of _____.
Answer:
Aggregate demand

Question 19.
_____ demand creates inflationary pressure.
Answer:
Excess demand

Question 20.
The aggregate demand curve slopes _____
Answer:
Upward

Question 21.
If aggregate demand falls short of aggregate supply the level of national income tends to _____
Answer:
Fall

III. Correct the Sentences:

Question 1.
National Income analysis is the subject matter of micro economics.
Answer:
Incorrect.
Correct – National Income analysis is the subject matter of macro economics.

Question 2.
Macro-economics deals with the economic affairs “in the large”.
Answer:
Correct.

Question 3.
Aggregate demand consists of consumption demand & saving.
Answer:
Incorrect.
Correct – Aggregate demand consists of consumption demand & investment demand.

Question 4.
Excess demand occurs prior to the full employent.
Answer:
Incorrect.
Correct – Excess demand occurs at the full employment.

Question 5.
Deficit demand arises after the full employment.
Answer:
Incorrect.
Correct – Deficit demand arises at the full employment.

Question 6.
The demand is effective when aggregate demand is equal to aggregate supply.
Answer:
Correct.

Question 7.
Excess demand creates inflation.
Answer:
Correct.

Question 8.
Aggregate supply is inversely related to level of employment.
Answer:
Incorrect.
Correct – Aggregate supply is directly related to level of employment.

Question 9.
Aggregate demand is the function of level of employment.
Answer:
Correct.

Question 10.
If aggregate demand is equal to aggregate supply, saving is equal to investment.
Answer:
Correct.

Question 11.
Consumption expenditure increases with the increase the income.
Answer:
Correct.

Question 12.
Consumption demand depends on price-level.
Answer:
Incorrect.
Correct – Consumption demand depands on the level of income.

Question 13.
Aggregate demand curve starts from the origin.
Answer:
Incorrect.
Correct – Aggregate supply curve starts from the origin.

Question 14.
When income is zero, consumption is zero.
Answer:
Incorrect.
Correct – When income is zero, consumption demand is positive.

Question 15.
Net export is always positive.
Answer:
Incorrect.
Correct- Net export may be positive or negative.

Question 16.
Equilibrium level of income is determined at that point where aggregate demand is equal to aggregate supply.
Answer:
Correct.

Question 17.
Autonomous investment depends on the level of national income.
Answer:
Incorrect.
Correct – Autonomous investment is independent of the level of national income.

Question 18.
Consumption is the function of income.
Answer:
Correct.

Question 19.
The theory of income determination by J.M. Kevnes is a long-run theory
Answer:
Incorrect
Correct – The theory of income determination bv J.M. Kevnes is a long-run theorvThe theory of income determination bv J.M. Kevnes is a short-run theory

Question 20.
If aggregate supply falls short of aggregate demand the level of national income decreases.
Answer:
Incorrect
Correct – If aggregate supply falls short of aggregate demand the level of national income increases. .

Question 21.
The defict demand creates prifce rise.
Answer: Incorrect
Correct – The defict demand creates price fall.

IV. Answer the following questions in one word:

Question 1.
What is aggregate demand?
Answer:
Aggregate demand refers to the total expenditure incurred on consumption & investment at aparticular time period.

Question 2.
What is aggregate supply?
Answer:
Aggregate supply refers to the total flow of final goods & services during a particular time period with given level of employment.

Question 3.
What is effective demand?
Answer:
Effective demand refers to that demand at which aggregate demand is equal to agregate supply.

Question 4.
What are the components of aggregate demand?
Answer:
Consumption demand, investment demand & net export constitute the aggregate demand.

Question 5.
What are the components of aggregate supply?
Answer:
Consumption & saving are the components of aggregate supply.

Question 6.
What is excess demand?
Answer:
Excess demand refers to the excess of aggregate demand over aggregate supply at full employment level. .

Question 7.
What is deficit demand?
Answer:
When aggregate demand falls short of aggregate supply at full employment level, it is called deficit demand.

Question 8.
What is saving?
Answer:
Saving is a residual income left after meeting the consumption expenditure.

Question 9.
How is equilibrium level of income determined?
Answer:
Equilibrium level of income is determined at that level where aggregate demand equals to aggregate supply.

Question 10.
From which term ‘Macro’ is derived?
Answer:
Macro is derived from the Greek word ‘Marcos’ which means large.

Question 11.
What is Net export?
Answer:
The residual amount between export & import is called Net export.

Question 12.
What is the relationship between aggregate demand and level of employment?
Answer:
There is direct functional relationship between aggregate demand & the level of employment.

Question 13.
What are the components of aggregate demand?
Answer:
Consumption demand, investment demand, government demand & net export are the components of demand.

Question 14.
What are the components of aggregate supply?
Answer:
Consumption & saving are the components of aggregate supply.

Question 15.
What do you mean by full employment?
Answer:
Full employment is a situation in which all the existing resources in the economy are fully employed.

Question 16.
What is autonomous consumption?
Answer:
Consumption which is independent of level of income is called autnomous consumption.

Question 17.
What is autonomous investment?
Answer:
The investment which is not influenced by income is called autonomous investment.

Question 18.
What happens to saving & investment at the point of equilibrium?
Answer:
Saving & investment are equal at the point of equilibrium.

Question 19.
What is investment demand?
Answer:
Investment demand refers to the demand for that part of national income which is employed to create capital for further production.

Question 20.
What is consumption function?
Answer:
The functional relationship between consumption & income is called consumption function.

Odisha State Board CHSE Odisha Class 12 Biology Solutions Chapter 3 Human Reproduction Textbook Questions and Answers.

CHSE Odisha 12th Class Biology Chapter 3 Question Answer Human Reproduction

Human Reproduction Class 12 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Choose the correct option

Question 1.
Which of the following is not a gonadotropin?
(a) FSH
(b) hCG
(c) LH
(d) Testosterone
Answer:
(d) Testosterone

Question 2.
Which of the following hormones is not a steroid?
(a) Relaxin
(b) Estradiol
(c) Progesterone
(d) Testosterone
Answer:
(a) Relaxin

Question 3.
Which of the following is not secreted by the acrosome?
(a) Hyaluronidase
(b) Corona penetrating enzyme
(c) Zonalysin
(d) Fertilizin
Answer:
(d) Fertilizin

Question 4.
Blastocyst formation follows
(a) fertilisation
(b) spermatogenesis
(c) gametogenesis
(d) cleavage
Answer:
(d) cleavage

Question 5.
Placenta secretes the hormone
(a) testosterone
(b) human chorionic gonadotropin
(c) oxytocin
(d) growth hormone
Answer:
(b) human chorionic gonadotropin

Question 6.
Fallopian tube is part of
(a) ureter
(b) oviduct
(c) uterus
(d) vas deferens
Answer:
(b) oviduct

Question 7.
In human, fertilisation usually occurs in the
(a) vagina
(b) cervix
(c) uterine cavity
(d) uterine tube
Answer:
(d) uterine tube

Question 8.
Which of the following is not a male secondary sexual character?
(a) Beard
(b) Enlarged penis
(c) Coarse voice
(d) Increased fat in the buttocks
Answer:
(d) Increased fat in the buttocks

Question 9.
The chief source of circulating oestrogen is
(a) theca interna
(b) granulosa
(c) theca externa
(d) stroma
Answer:
(a) theca interna

Question 10.
Which of the following is not an accessory sex organ?
(a) Testis
(b) Epididymis
(c) Bulbourethral gland
(d) Seminal vesicles
Answer:
(a) Testis

Question 11.
Delivery of a human baby following pregnancy is known as
(a) ovulation
(b) parturition
(c) abortion
(d) conception
Answer:
(b) parturition

Question 12.
Sertoli cells are regulated by
(a) GH
(b) LH
(c) FSH
(d) TSH
Answer:
(c) FSH

Question 13.
Which of the following is a source of progesterone?
(a) Corpus luteum
(b) Corpus spongiosum
(c) Corpus albicans
(d) Corpus haemorrhagicum
Answer:
(a) Corpus luteum

Question 14.
Milk ejection from the breasts of a woman following the birth of a baby is stimulated by
(a) LH
(b) FSH
(c) GH
(d) oxytocin
Answer:
(d) oxytocin

Question 15.
Find the mismatch
(a) Acrosome – Dissolution
(b) Tail – Nutrition
(c) Mitochondria – Energy production
(d) Centriole – Cleavage
Answer:
(b) Tail provides motility not nutrition.

Fill in the blanks

1. All but one X-chromosomes in human female cells are condensed and inactive. Such X-chromosomes are known as ___
Answer:
Barr body

2. The Testis Determining Factor (TDF) is a polypeptide, expressed by ___ gene present on the Y-chromosome.
Answer:
sry

3. The factor responsible for the regression of the mullerian duct in the human male foetus is known as ___ secreted by ___ cell of the testis.
Answer:
AMH, Sertoli

4. Gonadotropins (FSH and LH) are secreted from ___ .
Answer:
anterior pituitary gland

5. FSH stimulates the Sertoli cells to synthesise three polypeptides, namely inhibin ___ and ___ .
Answer:
activins, transferrin

6. The early development of the ovarian follicles is stimulated by ___ and oestrogen.
Answer:
FSH

7. Luteinizing hormone stimulates ___ cells of the testis.
Answer:
Leydig

8. The final maturation of the ovarian follicles and ovulation are stimulated by ___ .
Answer:
LH

9. The prostatic fluid contains an acid called ___ .
Answer:
citric acid

10. Prostate Specific Antigens (PSA) help in the diagnosis of ___ .
Answer:
prostate cancer

11. The swollen tip of the penis is known as ___ .
Answer:
glans penis

12. The erectile tissue of the penis is constituted by ___ and ___ .
Answer:
corpus cavernosa, corpus spongiosum

13. The seminal vesicles discharge into vas deferens through ___ .
Answer:
ejaculatory duct

14. The peritoneal fold by which the ovary is attached to the broad ligament is called ___ .
Answer:
mesovarium

15. The primary oocytes are arrested at ___ stage of first meiosis until the onset of puberty.
Answer:
diplotene

16. The layers of cuboidal follicular cells surrounding the primary oocyte constitutes ___ .
Answer:
granulosa cells

17. Stromal cells, surrounding the granulosa cells are known as ___ cells.
Answer:
thecal

18. The egg is ovulated at ___ stage.
Answer:
ovulatory/secretory

19. The non-cellular layer surrounding the primary oocyte is known as ___ .
Answer:
corona radiata

20. The inner epithelial lining of the uterus is known a s ___ .
Answer:
endometrium

21. The menstrual cycle spans ___ days and the ovulation occurs on the day ___ .
Answer:
28, 14

22. The secondary oocyte is arrested at ___ before fertilisation.
Answer:
metaphase-II

23. Penetration of spermatozoan into the egg at fertilisation triggers metaphase-II in the secondary oocyte. This phenomenon is known as ___ .
Answer:
egg activation

24. Following the failure of fertilisation, the corpus luteum regresses into a structure called ___
Answer:corpus albicans

25. Corpus luteum is the main source of oestrogen and ___ .
Answer:progesterone

Answer each of the following in one word or more words, whenever necessary

1. Retention of testis in the abdominal cavity.
Answer:
Cryptorchidism

2. The canal through which the testis descends into the scrotum.
Answer:
Inguinal canal

3. The plexus of blood capillaries that helps maintain the temperature of the testis for normal functioning.
Answer:
Pampiniform plexus

4. The connective tissue capsule of the testis.
Answer:
Tunica albuginea

5. The seminal fluid contains a monosaccharide as the energy source.
Answer:
Fructose

6. The passage through which both the urine and semen are discharged.
Answer:
Urethra

7. The glans penis is covered by a fold of loose skin.
Answer:
Prepuce

8. The forcible expulsion of semen through the urethra.
Answer:
Ejaculation

9. The low count of sperms in human semen.
Answer:
Oligospermia

10. The mucopolysaccharide layer surrounding a primary ovarian follicle.
Answer:
Layer of granulosa cells

11.The hillock of granulosa cells connecting the granulosa cells surrounding the oocyte with the peripheral granulosa cells layer in a Graafian follicle.
Answer:
Cumulus oophorus

12.The loose mass of connective tissue, in which are present different stages of ovarian follicles.
Answer:
Medulla of ovary

13. The regressing follicles and the act of regression.
Answer:
Atretic follicles and follicular atresia

14. The uterine layer that is sloughed off during menstrual cycle.
Answer:
Endometrium

15. The arteries of the uterine wall that undergo disintegration during the menstrual cycle.
Answer:
Basal and spiral arteries

16. The height of LH secretion, 16-26 hours before ovulation.
Answer:
LH surge

17. The tissue formed by the apposition of both the maternal and foetal tissues during pregnancy.
Answer:
Placenta

18. The modified sweat glands in the female that serve as the source of food for neonatal babies.
Answer:
Alveoli

19. The fertilizin-antifertilizin reaction that stops the march of a large number of sperms towards the egg.
Answer:
Agglutination reaction

20. The penetration of the spermatozoan into the egg sets in a reaction in the cortical cytoplasm, which results in the formation of fertilisation membrane.
Answer:
Cortical reaction (slow block)

Short Answer Type Questions

Question 1.
What are the disadvantages of asexual reproduction?
Answer:
Disadvantages of asexual reproduction

• There is no mixing of genetic material, therefore, no variation takes place.
• Since, variations do not occur, asexual reproduction has no role in evolution.
• Due to rapid multiplication, it causes overcrowding.
• The organisms produced through asexual reproduction have low adaptability to the changed environment.

Question 2.
Explain sexual dimorphism.
Answer:
Sexual dimorphism means presence of male and female reproductive organs in different individuals. Such individuals are called dioecious or unisexual. Male and female exhibits different body type structurally and functionally. .

Question 3.
How do gametes acquire haploid number of chromosomes?
Answer:
The haploid number of chromosomes in gametes is contributed by the process called gametogenesis from the undifferentiated diploid germ cells in the gonads.
It is called spermatogenesis in males and oogenesis in females.

Question 4.
Is a Y-chromosome essential for the development of testis in human? Explain.
Answer:
Yes, Y-chromosome is necessary for the development of testes in humans. It contains sry gene which encodes for Testis Determining Factor (TDF) in foetus. In the presence of TDF, foetus develops into male, else female sex is developed.

Question 5.
What is the role of antimullerian hormone? Where is it secreted from?
Answer:
Antimullerian Hormone (AMH) helps in the testicular descent to the inguinal region. This dimeric glycoprotein is produced by Sertoli cells throughout the childhood in males and declines after puberty.

Question 6.
Explain, what is puberty?
Answer:
Puberty is a period when reproductive organs start functioning. It is attained between 13-16 years and gonadotropins play an important role in it. This period is marked by the development of sexual secondary structures in both the sexes and menarche in females only.

Question 7.
Name two gonadotropins. Where are these secreted from?
Answer:
Luteinizing hormone and follicle stimulating hormone are the gonadotropins secreted by anterior lobe of pituitary under the influence of Gonadotropin Releasing Hormone (GnRH) secreted by hypothalamus. In females, oestrogen is also secreted along with LH and FSH.

Question 8.
Describe the major role of LH in both male and female.
Answer:
In males, LH may be called Interstitial Cells Stimulating Hormone (ICSH) because it stimulates the interstitial or Leydig’s’ cells of the seminiferous tubules of the testes to secrete androgens. In females, LH stimulates the corpus luteum to secrete progesterone.
High level of LH on the day 14 of menstrual cycle results in the release of secondary oocyte from the mature Graafian follicle. This process is called ovulation which is the result of LH surge on day 14.

Question 9.
What is a cremasteric reflex?
Answer:
In cold wheather, the testes are elevated by the contraction of a band of muscle, known as cremasteric muscle to get the warmth of the trunk. This effect is called cremasteric reflex. The same effect occurs when the thigh of a man is stroked.

Question 10.
Explain the counter-current heat exchange mechanism in human testis.
Answer:
Testicular arteries that descend into the scrotum are surrounded by a plexus of veins, which ascend the testis and form a pampiniform plexus. Blood that returns from the testes through these plexus is cooler than the blood in testicular arteries.
The arterial blood is cooled by venous blood by a counter-current heat exchange mechanism.

Question 11.
Describe the functions of the Sertoli cells.
Answer:
Sertoli cells or subtentacular cells are present in between the germinal epithelial cells of seminiferous tubules.
They provide nourishment to the developing spermatozoa. These cells secrete Androgen Binding Protein (ABP) that concentrates testosterone in the seminiferous tubules. It also secretes inhibin protein which suppresses FSH synthesis.

Question 12.
What is blood testis barrier? How does it help the testis?
Answer:
The basal lamina of the germinal epithelium, muscle-like myoid cells at the base of basal lamina and tight junction between adjacent Sertoli cells constitute a blood testis barrier. This barrier prevents many macromolecules from moving into the tubular lumen.

Question 13.
What are the functions of epididymis?
Answer:
Epididymis is a mass of long narrow closely coiled tubule, which lies along the inner side of each testis. It stores the sperms and secretes a fluid which nourish the sperms.

Question 14.
Name five secondary sexual characters in human male.
Answer:
Secondary sexual characters in males include muscular build up, beard, moustaches, underdeveloped mammary glands, high BMR, predominantly abdominal breathing, etc.

Question 15.
What do you mean by accessory sex organs? Give five examples in human male.
Answer:
Accessory sex organs are those that do not produce gametes but they are essential for reproduction. In males scrotum, epididymis, vasa deferentia, ejaculatory ducts, urethra and penis are the example of accessory sex organs.

Question 16.
What is the function of the prostate glands
Answer:
The prostate gland is a single large gland that surround the urethra. It produces a milky secretion with pH 6.5 which forms 25% of the volume of semen. This secretion contains citric acid, enzymes and prostaglandins secretions of prostate gland nourishes and activates the spermatozoa to swim.

Question 17.
What is the role of corpus luteum following fertilisation and implantation?
Answer:
Corpus luteum acts as a temporary endocrine gland. It secretes large amount of progesterone which is essential for the maintenance of endometrium, necessary for implantation of the fertilised egg and other events of pregnancy. It degenerates in the absence of fertilisation.

Question 18.
Explain LH surge.
Answer:
When the blood level of oestrogen rises to a peak near the middle of the cycle, it gives positive feedback and stimulates more LH secretion. It is called LH surge and it stimulates ovulation.

Question 19.
What is spermiogenesis?
Answer:
Formation of spermatozoa (Spermiogenesis) Each haploid spermatid is a typical immotile cell containing a haploid nucleus, cytoplasm and cytoplasmic organelles. The metamorphosis of spermatids into motile sperms occurs because a sperm possesses many structures which are not typical to a spermatid.

All the structures confer motility to the sperm. After spermiogenesis, sperm heads are embedded in the Sertoli cell and finally released from the seminiferous tubule by the process of spermiation.

Question 20.
What is the role of acrosome in fertilisation?
Answer:
The sperm head contains an oval haploid nucleus, the anterior part of which is capped by structure called acrosome.
The acrosome secretes enzymes that help dissolve the egg barriers during fertilisation. The sperm lysins present in acrosome include hyaluronidase, corona penetrating enzyme and acrosis. They digest zona pellucida and corona radiata and help the sperm to enter the egg.

Question 21.
Placenta is an endocrine tissue. Explain.
Answer:
The placenta acts as an endocrine tissue and produces several hormones like human Chorionic Gonadotropin (hCG), human Placental Lactogen (hPL), oestrogen, progesterone, etc. In the later phase of pregnancy, a hormone called relaxin is also secreted by the placenta. Hormones such as hCG, hPL and relaxin are produced in women only during pregnancy. In addition, during pregnancy the levels of other hormones like oestrogens, progesterone, cortisol, prolactin, thyroxine, etc., are increased several fold in the maternal blood. Increased production of these hormones is essential for supporting foetal growth, metabolic changes in the mother and maintenance of pregnancy.

Question 22.
Enlist the hormones regulating menstrual cycle and mention the role of each.
Answer:
The hormones that regulate menstrual cycle along with their functions are
1.Pituitary gonadotropins (LH, FSH and Oestrogen) These help in the proliferation of Graafian follicle and endometrium of uterus.

• FSH Stimulates the growth of ovarian follicle and secretion of oestrogen.
• Oestrogen Increased level of oestrogen gives positive feedback and stimulates more LH production.
• LH Stimulates ovulation.

2. Progesterone Essential for the maintenance of endometrium.

Question 23.
What do you understand by follicular atresia? Where does it occur?
Answer:
At birth around 2.5 millions of primary follicles are found in each ovary but at puberty only 60,000-80,000 primary follicles are left. The rest degenerate, in a process called follicular atresia. It occurs in the ovaries of females.

Question 24.
Where do the granulosa and thecal cells originate from and what are their functions?
Answer:
Granulosa cells and thecal cells surround the primary follicles to form secondary follicles in the ovaries. The innermost layer of granulosa cells that surround the oocyte is known as the corona radiata. A glycoprotein protective layer, known as the zona pellucida appears between the oocyte and corona radiata. Cells from the stroma surround the granulosa cells and differentiate as the thecal cells.
During ovulation, granulosa and thecal cells proliferate and become glandular.
They collectively form luteal cells which is the source of oestrogon and progesterone.

Question 25.
How is the mammary gland hormonally regulated?
Answer:
Mammary glands are modified sweat glands that lie over the pectoral muscles. In the female, breasts are undeveloped until puberty. At puberty they begin to develop under the influence of oestrogen and progesterone.
The glands proliferate during pregnancy and start producing milk towards the end of pregnancy by the process called lactation.
It is induced by hormones like Prolactin (PRL) and oxytocin secreted from the mother’s pituitary gland. Lactation helps the mother in feeding the newborn.
Milk production is stimulated by prolactin and ejection of milk is induced by oxytocin.

Write brief notes on the following

Question 1.
Secondary sexual characters
Answer:
Secondary sexual characters are those which help distinguish the two sexes morphologically. The appearance of these characteristics is influenced by the secretion of hormones at the onset of puberty. Testosterone and oestrogen are responsible for the production of secondary sexual characters in males and females, respectively.

Testosterone is involved in greater bone density, high muscle mass, larger voice box, beard and moustaches development, etc.
Oestrogen is involved in breast development, increased* fat tissue around hips, wider pelvic bone, etc. ’ .

Question 2.
Accessory sex organs
Answer:
Reproductive organs other than testes and ovaries are called accessory sex organs. These organs help in the maturation of sex cells. In males, they include seminal vesicles, prostate gland and Cowper’s/ Bulbourethral glands. In female reproductive system, accessory sex organ includes Bartholin’s gland.

Question 3.
Seminiferous tubule
Answer:
The seminiferous tubules are the site of germination, maturation and transportation of sperm cells within the male testes. They are made up of columnar Sertoli cells surrounded by spermatogenic cells on the epithelial interior. They are located within the testes and are formed from the testis cords that develop from the primitive gonadal cords formed gonadal ridge.

Question 4.
Graafian follicle
Answer:
Graafian follicle is a mature fluid-filled cavity in a mammalian ovary that ruptures during ovulation to release an egg on the day of ovulation. Graafian follicle represents the follicular stage after the first meiotic division but before ovulation.
It is characterised by a large antrum that makes up most of the follicle. The secondary oocyte is surrounded by zona pellucida and a layer of corona radiata.

Question 5.
Corpus luteum
Answer:
The corpus luteum is a temporary endocrine structure in female that is involved in ovulation and early pregnancy. This yellow body is formed in ovary Graafian follicle that has matured and released its ovum. The corpus luteum is made up of lutein cells which develop immediately following ovulation, when yellow pigment and lipids accumulate within the granulosa cells lining the follicle.

The corpus luteum secretes oestrogen and progesterone which helps in setting the suitable environment for pregnancy. In the absence of pregnancy, this structure regresses and gets converted into white body called corpus albicans.

Question 6.
Prostate gland
Answer:
The prostate gland is located between the bladder and the penis just in front of rectum in males. It secretes fluid that nourish and protect sperms. Its secretions are alkaline and milky in appearance and it constitutes about 30% of the volume of semen. The alkalinity of semen helps to neutralise the acidity of vaginal tract. Inflammation of prostate gland causes prostatitis which may be benign or cancerous.

Question 7.
Seminal vesicles
Answer:
The seminal vesicles are a pair of tube-like glands in males. They are found behind the bladder and their secretion makes about 70% of the content of semen.

The secretion of seminal vesicle is rich in sugars (especially fructose) which feeds the sperms. The fluid also has clotting properties that makes the semen sticky. Prostaglandins in seminal fluid are believed to aid fertilisation by causing the mucous lining of the cervix to be more receptive to sperm as well as by aiding the movement of sperm towards the ovum with peristalic contractions of uterus and Fallopian tubes.

Question 8.
Bulbourethral gland
Answer:
The bulbourethral gland, also called Cowper’s gland are exocrine glands in males,. They are homologous to Bartholin’s glands in females. They are compound tubulo-alveolar glands located posterior and lateral to the membranous portion of the urethra at the base of penis. Their secretion contribute about 0.1-0.2 mL of the ejaculate. It is a clear fluid that is rich in mucoproteins. The secretion helps to lubricate the distal urethra and neutralise the acidic urine which remains in the urethra.

Question 9.
Blood testis barrier
Answer:
The Blood Testis Barrier (BTB) is one of the tightest blood tissue barriers in mammalian body. It divides the seminiferous epithelium into the basal and apical compartments. Meiosis-I and II, spermiogenesis and spermiation all occur in a specialised microenvironment behind BTB in the apical compartment but spermatogonial renewal and differentiation and cell cycle progression up to preleptotene spermatocyte stage takes place outside of the BTB in the basal compartment.

BTB is different from most other tissue barriers in that it is not only comprised of tight junctions. Desmosomes, gap junctions and ectoplasmic specialisations also occur in it.

Question 10.
Luteal phase
Answer:
The luteal phase is one stage of menstrual cycle. It occurs after ovulation. It begins with the formation of corpus luteum and ends in either pregnancy or luteolysis, i.e regression of corpus luteum. The main hormone associated with this stage is progesterone which is secreted by corpus luteum. This phase lasts between 10-16 days. Luteal phase of less than 12 days may make it difficult to achieve pregnancy.

Question 11.
Menopause
Answer:
Menopause (Gr. Men = month, pausis = cessation)
It is a phase in woman’s life when ovulation and menstruation stop. It occurs between 45-55 years of age. Some women have irregular cycles for, months or years prior to menopause. Others simply stop menstruating abruptly.

Cause One theory is that menopause is a result of changes in pituitary gland and the nearby hypothalamus. Another theory suggests that menopause may begin when no follicles are left in the ovaries. In fact decline in oestrogen and progesterone level leads to menopause. Symptoms The uterus and the vagina gradually become atrophic (decreased work). Women may suffer temporarily depression, hot flashes, and other physiological and psychological problems in menopause. Most of these symptoms can be relieved by taking hormones prescribed by a physician. But this replacement of hormones is not encouraged due to some side effects.

Question 12.
Gonadotropins
Answer:
Gonadotropins are glycoprotein polypeptide hormones secreted by gonadotroph cells of the anterior pituitary gland. These are stimulated by Gonadotropin Releasing Hormones (GnRH) secreted by hypothalamus. The major gonadotropins are Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). They stimulate the gonads, i.e. testes and ovaries in males and females, respectively.

Question 13.
Placenta
Answer:
Placenta is the intimate connection between the foetus and uterine wall of the mother to exchange the materials. In humans, chorion takes part in the formation of placenta hence called chorionic placenta. It consists of foetal part, the chorion and a maternal part, the decidua basalis.

The degree of intimacy is so strong that the blood vessels of the chorionic villi are bathed in the mother’s blood. This type of placenta which is based on the intimacy between foetal and maternal parts of the placenta is referred to as haemochorial placenta. It provides nutrition, aids in respiration and excretion of the foetus.

Question 14.
Parturition Or What is parturition?
Answer:
Parturition is the act of expelling the full term young one from the mother’s uterus at the end of gestation period.
It is induced by both nervous system and hormones secreted by the endocrine glands of the mother. The signals for childbirth (parturition) originates from the fully matured foetus and placenta which induce mild uterine contractions called foetal-ejection reflex.

This causes quick release of oxytocin from maternal posterior lobe of pituitary. The amount of oxytocin is increased just before and during labour pains which promote contractions of the uterine muscles. Relaxin increases the flexibility of the pubis symphysis and helps to dilate the uterine cervix.

Question 15.
Spermiogenesis
Answer:
Spermiogenesis is the process of transformation of spermatids into spermatozoa (sperms). Four sperms are formed from one spermatogonium by the differentiation process. After spermiogenesis, sperm head becomes embedded in the Sertoli cells and are finally released from the seminiferous tubules by the process called spermiation. Spermiogenesis is also called spermateliosis.

Question 16.
Lactation
Answer:
Lactation is the process of production of milk in the mammary glands of females towards the end of pregnancy and after the birth of the young one. Secretion and storage of milk generally begins after birth of young one, usually within 24 hours under the influence of prolactin (PRL) hormone secreted by anterior lobe of pituitary gland.

However, the ejection of milk is stimulated by the Hormone Oxytocin (OT) released from the posterior lobe of pituitary gland.
The first milk which comes from the mammary glands of mother just after childbirth, for 2-3 days is called colostrum.

Differentiate between two words in the following pairs of words

Question 1.
Leydig cell and Sertoli cell
Answer:
Differences between Leydig cells and Sertoli cells are as follows

Leydig’s cells (Interstitial cells)	Sertoli cells (Sustentacular cells)
They are present in between the seminiferous tubules.	They are present in between the germinal epithelial cells of the seminiferous tubules.
Leydig’s cells are found in small groups and are rounded in shape.	Sertoli cells are found singly and are elongated.
They secrete androgens (e.g. testosterone) male sex hormones.	They provide nourishment to the developing spermatozoa (sperms), Sertoli cells secrete ABP(Androgen Binding Protein) that concentrates testosterone in the seminiferous tubules. It also secretes another protein inhibin which suppresses FSH synthesis.

 

Question 2.
Corpus haemorrhagicum and Corpus luteum
Answer:
Differences between corpus haemorrhagicum and corpus luteum are as follows

Corpus haemorrhagicum	Corpus luteum
It is a temporary structure formed immediately after ovulation from the ovarian follicle as it collapses and is filled with blood that clots quickly	It is formed from corpus haemorrhagicum formed after the release of secondary oocyte after ovulation.
Non- endocrine.	Thmporary endocrine.

 

Question 3.
Follicular phase and Luteal phase
Answer:
Differences between follicular phase and luteal phase are as follows

Follicular phase	Luteal phase
It extends for about 10-12 days usually from day 6-13 in a 25 days cycle.	It extends for about 13-14 days after ovulation usually from day 15-28 in a 28 days cycle.
Primary follicle changes into Graafian follicle.	Empty Graafian follicle changes into corpus luteum.
Oestrogens are secreted.	Progesterone is secreted.
Endometrium is about 2-3 mm thick. The uterine glands do not secrete watery secretion.	Endometrium is about 5 mm thick. The uterine glands secrete watery secretion.

 

Question 4.
Antral follicle and Graafian follicle
Answer:
Differences between antral follicle and Graafian follicle are as follows

Antral follicle	Graafian follicle
Formed from secondary follicle.	Formed from tertiary follicle.
Cellular differentiation are at peak.	Cellular differentiation is completed.
Occur in follicular phase.	Occur in ovulatory phase.
Under the influence of FSH, it gets converted in Graafian follicle.	Under the influence of LH, it ruptures to release secondary oocyte and gets converted into corpus luteum.

 

Question 5.
Granulosa and Thecal cells.
Answer:
Differences between granulosa cells and thecal cells are as follows

Granulosa	Thecal cells
Inner,ost cells that surrounds the oocyte.	Cells of that stroma surround granulosa cells.
After ovulation, they become the source of progesterone.	After ovulation, they become the source of oestrogen.

 

Question 6.
First maturation division and Second maturation division.
Answer:
Differences between first maturation division and second maturation division are as follows

First maturation division	Second maturation division
The primary oocyte divides into two unequal haploid daughter cells a large secondary oocyte and a very small first polar body.	The first polar body may divide to form second polar bodies. The secondary oocyte again divide into unequal daughter cells a large ootid and a very small second polar body.

 

Question 7.
Spermatogenesis and Oogenesis.
Answer:
Differences between spermatogenesis and oogenesis are as follows

Spermatogenesis	Oogenesis
It occurs in the testes.	It occurs in the ovaries.
Spermatogonia change to primary spermatocytes.	Oogonia change to primary oocytes.
A primary spermatocyte divides to form two secondary spermatocytes.	A primary oocyte divides to form one secondary oocyte and one polar body.
A secondary spermatocyte divides to form two spermatids.	A secondary oocyte divides to form one ootid and one polar body.
No polar body is formed.	Polar bodies are formed.
A spermatogonium forms four spermatozoa.	An oogonium forms one ovum.
Sperms are minute, yolkless and motile.	Ova are much larger often with yolk and non-motile.
It is generally completed in the tests and thus mature, sperms are released from the tests.	It is often completed in the female reproductive tract or in many animals in water because oocytes are released from the ovaries.

 

Long Answer Type Questions

Question 1.
Discuss about different methods of asexual reproduction in animal, as studied by you.
Answer:
In asexual reproduction, a single parent gives rise to two or more young ones that have hereditary – traits similar to that of parent. It occurs by various processes like fission, budding, etc. It is mostly found in lower groups of organisms like some plants, protozoans, sponges, coelenterates, etc.

Question 2.
Describe the male reproductive system in human.
Answer:
Male Reproductive System:
The male reproductive system is located in the pelvis region. It consists of scrotum a pair of testes, excurrent ducts and accessory glands.

Scrotum:
It is a pouch-like structure of pigmented skin arising from the lower abdominal wall and hanging between the leg. It is divided internally into right and left scrotal sacs by a muscular partition called septum scrota. The testis originates in the abdominal cavity, but later during the seventh month of development, it descend into the respective scrotal sacs through the passages called inguinal canals.

Testicular descent to inguinal region during gestation period is affected by Antimullerin Hormone (AMH) secreted by Sertoli cells. 90% of babies have completely descended testes, when they are born. In 10% of new-borns, testes fail to descend and retained in the abdominal cavity. This condition is called cryptochidism. It can be treated by gonadotropins or surgery.

In cold weather, the testes are elevated by the contraction of a band of muscle, known as cremasteric muscle to get the warmth of the trunk. This effect is known as cremasteric reflex.

The same effect occurs when the thigh of a man is stroked. In the baby, this stimulus causes the testes to ascend up into the abdominal cavity through the inguinal canal.

Functions of Scrotum:
Scrotum keeps the temperature of testes about 2-2.5°C lower than the internal body temperature, which is essential for the production of sperms, i.e. spermatogenesis. This temperature is maintained by perspiration and evaporation from the scrotal surface. These processes occur due to the presence of pampiniform plexus that surround testiculae arteries which ascend from the testis. Venous blood returning from testis through pampiniform plexus is cooler than the blood in testicular arteries. The countercurrent heat exchange mechanism between the arterial and venous blood cools down the arterial blood.

Testes: Microscopic Anatomy:
Testes are the primary sex organs in men. These are the male gonads, i.e. the site where the male gametes or sperms are made. A pair of testis is situated outside the abdominal cavity within the scrotum. Each testis is oval in shape and measures about 4-5 cm in length and 2-3 cm in width. These are suspended in the scrotum by spermatic cords.

Microscopic Anatomy:
The outermost covering of the testis is formed by a dense connective tissue called tunica albuginea. It thickens and extends inwardly into each testis as mediastinum testis which further forms thin connective tissue septum. The latter divides each testis into 200-300 compartments called testicular lobules. Each lobule contains 1-3 highly convoluted seminiferous tubules that is lined by stratified cuboidal epithelium.

Seminiferous Tubule:
It is the structural and functional unit of testis in which sperms are produced. Each seminiferous tubule is present in the mass of loose connective tissue that contain fibroblast, epithelial cells, nerves, blood and lymphatic vessels, etc. Inside these tubules, two types of highly specialised cells are present namely Sertoli cells (nurse cells) and spermatogenic cells.

Transverse section through human testis : (a) A single seminiferous tubule with cells of Leydig in the interstitial tissue, (b) A magnified part of the seminiferous tubule showing the blood-testis barrier, Sertoli cells and its relationship to the differentiating spermatogenic cells and (c) A Sertoli cell with spermatogenic cells in different stages of development

1. Spermatogenic cells These are majority of dividing cells or male germ cells (cuboidal cells) which produce spermatogonia by mitotic division. The spermatogonia further grows into primary spermatocytes and undergo meiosis producing haploid cells, first secondary spermatocytes and then spermatids.

2. Sertoli or Sustentacular cells They are tall, pyramidal, non-dividing somatic cells. They serve the supporting and nourishing function for the spermatogenic cells in different stages of their differentiation. The basal lamina of the germinal epithelium, muscle-like myoid cells at the base of the basal lamina and tight junctions between adjacent Sertoli cells constitute a blood testis barrier which performs the following functions

• Prevents many macromolecules from moving into the tubular lumen.
• Prevents the blood borne noxious chemical agents from entering into the tubule.
• Prevents the passage of antigenic agents from the tubule into the blood, which are likely to generate an autoimmune response.

The region outside the seminiferous tubules called interstitial spaces contain small blood vessels and masses of cells called interstitial cells or Leydig cells. These cells synthesise and secrete the testicular hormones called androgens. Leydig cells are endocrine in function and thus, regulate and maintain male sex characteristics. Other immunologically competent cells are also present in this region.

Accessory or Excurrent Duct System:
These ducts store and transport the sperms along with other glandular secretions from the testis to the outside through urethra. The male’s sex accessory ducts include-tubuli recti, rete testis, vasa efferentia (intratesticular ducts), epididymis, vas deferens and urethra (extratesticular ducts). The ends of seminiferous tubules converge and join to form short straight tubules called tubuli recti.

Duct system in human testis

The tubuli recti open into a network of wider, irregular tubules called rete testis, that further open into 12 short efferent ductules or ductuli efferentes.

The latter open into the epididymis and carry sperms outside the testis. Epididymis is a long tube, which is greatly coiled and tightly packed to form an elongated flattened body. It is located along the posterior surface of each testis.

Sperms undergo physiological maturation, acquiring increased motility and fertilising capacity (i.e. capacitation) in epididymis. After that, they pass down to the tail of epididymis, where they stay for a very short period before entering the two vas deferens or ductus deferens.

The vas deferens ascends to the abdomen and lopps over urinary bladder. It receives a duct from seminal vesicle to form ejaculatory duct. The ejaculatory duct enters the prostate gland and opens into the prostatic urethra.

The prostatic urethra extends through the penis to its external opening called urethral meatus or penile urethra. The urethra carries urine from bladder as well . as spermatozoa and secretions from the Cowper’s and prostate glands.

Accessory Glands:
The accessory glands or the secondary glands in males are described below
1. Prostate gland It is a single gland that lies » inferior to the bladder. It receives two ejaculatory ducts that joins to form prostatic urethra. The latter receives ductules from prostate. It secretes a milky, slightly alkaline fluid, that contains lipids, enzymes, citric acid, etc.

It is released during ejaculation and helps to neutralise the acidic medium of vagina, making sperms more active to swim. Prostatic fluid accounts for nearly 20-30% of semen volume.

2. Seminal vesicles This paired gland is present posterior to the bladder above prostate. Its ducts empties in the ampulla of ductus deferens.
They secrete mucus and a watery alkaline fluid that contains fructose (acts as an energy source for the sperms). Prostaglandins (stimulate uterine contractions for sperm movement) and a clotting protein form a temporary clot after ejaculation. Later, fibrolysins dissolves the coagulate or clot so that it assume a liquid form. Calcium and certain other enzymes are also a part of seminal plasma.

Fructose, produced by seminal vesicles, is not present elsewhere in the body. Therefore, during forensic test for rape, its presence in females genital tract confirms sexual intercourse. The seminal vesicles and prostrate degenerates or atrophy after the removal of testes because they are androgen dependent glands.

3. Bulbourethral or Cowper’s gland These are situated beneath the bladder and behind the urethra. There ductules discharge into the prostatic urethra. They secrete mucus and an alkaline fluid into the urethra. The mucus helps in the lubrication of penis and neutralises any urinary acids in urethra

Questions 3.
Describe the female reproductive system in human.
Answer:
Female Reproductive System:
It consists of a pair of ovaries, glands, a duct system and many supporting structures. Its components are found in both paired and unpaired condition.

The female reproductive system consists of the following organs
Ovaries:
Ovaries are the primary sex organs of female that is situated in the pelvic cavity.
They produce female gametes (ovum) and several steroid hormones (ovarian hormones). The ovaries are almond-shaped, lying in the lower part of the abdomen and held to the broad ligament by double folds of peritoneum called mesovarium. Each ovary is about 2-4 cm in length and is connected by an ovarian ligament to the uterus and by a suspensory ligament to the lateral pelvic wall. Each ovary is covered by a thin epithelium layer called germinal epithelium.

Next to this layer, dense irregular connective tissue mass called tunica albuginea is present. Inner to this, cortex is present which is followed by highly vascularised connective tissue called cortex or stroma ovarian stroma, which contains connective tissues, blood vessels and mature follicles. The stroma is divided into two parts, i.e. a peripheral cortex and an inner medulla or stroma. There is no distinct boundary between the cortex and medulla.

Microscopic Anatomy of Ovary:
The production of eggs in females begins before birth, i.e. during the embryonic development stage, but is completed only after fertilisation. It takes place in ovaries. Cells of germinal epithelium undergo mitotic or equational division during multiplication phase, producing undifferentiated germ cells called oogonia or egg mother cells within each foetal ovary. These cells enter into the phase of maturation and start two meiotic divisions to enter prophase-I of meiotic division as primary oocytes. They get temporarily arrested at diplotene state and remains as such until the onset of puberty.

Primordial and primary follicles in the cortex of the ovary

Each primary oocyte then gets surrounded by a single layer of squamous follicle cells and is called the primordial follicle. About 2 million of these follicles exist in ovarian cortex of females before birth. A large number of these follicles degenerate during the phase from birth to puberty. Therefore, at puberty only 60000-80000 primary follicles are left in each ovary.

The primordial follicles get surrounded by more layers of cuboidal granulosa cells and a new theca. This process is stimulated by the pituitary gonadotropins-FSH and LH. Later the squamous follicular cells of primordial follicle changes to cuboidal or low columnar cells. This follicle is called primary follicle.

The follicular cells of primary follicle divide by mitosis and forms the new cuboidal-shaped granulosa cells. At this stage follicle is called secondary follicle.

The innermost layer of granulosa cells is corona radiata that surrounds the oocyte. Between the oocyte and eorona radiata, a glycoprotein layer called zona pellucida appears. The stromal cells that surround granulosa cells differentiate to form thecal cells. These cells differentiate as an outer theca externa and inner theca interna.

A thin basement membrane separates granulosa cells from the theca interna. This follicular stage is known as mature or Graafian follicle stage.

Structure of a Graafian (mature) follicle : A part(inset) is magnified to show the elaborate structure of the egg with the associated follicle cells

Development of Ovarian Follicle:

1. The primary follicle grow in size and a fluid called liquor folliculi or follicular fluid accumulates in a cavity called antrum of granulosa cells. These follicles with an antrum are called antral or secondary follicles.
2. The synthesis of liquor folliculi continues, antrum grows in volume and further segregation of granulosa cells occur. Due to this, few cells surround the oocytes and some other are displaced to periphery.
3. Theca externa cells form multiple layers around theca interna cells which leads to the formation of mature or Graafian follicle. At this stage, the first meiosis of primary oocyte gets completed to form a secondary oocyte.
4. The Graafian follicle, ruptures to release the secondary oocyte from the ovary.
5. The secondary ooctye is captured by the fimbriae of Fallopian tube which transport it to the uterus.
6. The remaining portion of Graafian follicle gets filled with blood to form corpus haemorrhagicum.
7. The theca and granulosa cells proliferate and become glandular to form theca lutein and granulosa lutein cell, respectively. These lutein cells are the source of oestrogen and progesterone. This post ovulatory follicle is called corpus luteum (endocrine structure) which secrete estradiol, progesterone and relaxin (peptide hormone).

Fate of Corpus Luteum:

• If fertilisation occurs Corpus luteum persist and no mensuration occurs, zygote undergoes embryonic development and implants in the endometrium of uterus.
• If fertilisation does not occur Corpus luteum degenerates to form corpus albicans and menstruation occurs.
  

Not all ovarian follicles reach maturity. Only one dominant follicle gets matured and ovulated. Rest of them degenerates by the process called follicular atresia and the resultant follicles are known as atretic follicles which are replaced by connective tissue.

Fallopian Tube (Uterine Ducts):
These are two small accessory tubes of 10-12 cm length, lying on either sides of uterus near the kidney. These tubes carry the egg from the ovary to the uterus and also provides the appropriate environment for its fertilisation.

The Fallopian tubes or oviducts show four regions, i.e. infundibulum, ampulla, isthmus and interstitial region,
(i) Infundibulum is broad and funnel-shaped with its edges bearing motile, finger-like projections called fimbriae. It helps in the collection of ovum after ovulation.

Female reproductive system
(ii) Ampulla is the long, wide, thin-walled part of the Fallopian tube next to the infundibulum where fertilisation takes place.
(iii) Isthmus is a short narrow lumen that follows ‘ ampulla and joins the uterus.
(iv) Interstitial region passes through the uterine wall and communicates with the uterine cavity.

Uterus (Womb):
It is about 7.5 cm long, 5 cm wide, like an inverted pear in shape. It is supported by ligaments attached to the pelvic wall. It lies between the urinary bladder and rectum.

Uterus has a thick, highly vascular wall, composed of three layers of tissues

• Outer perimetrium A thin single-layered membranous covering of uterus wall that is composed of squamous epithelial cells.
• Middle myometrium A thick layer of smooth muscle fibres, which contracts strongly during the delivery of the baby.
• Inner endometrium A glandular layer with many blood vessels. It consists of simple cuboidal or columnar epithelium. It undergoes cyclic changes during the menstrual cycle.

Blood Supply to Uterus:
The arteries that supply blood to uterus gets divided into arcuate arteries and spreads in the myometrium. The arcuate arteries further gets divided into parts so as to supply blood to endometrium.
These include

• Straight arteries These are short, supply blood to basalis layer.
• Spiral arteries These are long and coiled, supply blood to functionalis layer. Decreased supply to this layer during menstruation causes it to degenerate and cast off.

The endometrium descends into the lamina propria and form numerous uterine glands. Functionally, the layer is divided into two layers

• Luminal stratum functionalis During menstruation, this layer cast off along with blood vessels and uterine glands.
• Stratum basalis It helps to form a new functionalis layer.

Functions of Utreus:
Uterus receives the ovum from the Fallopian tube, forms placenta for the development of foetus and also expels the young one at the time of birth.

Cervix:
It is the narrow entrance of the uterus into the vagina. It has strongest sphincter in its wall and is normally blocked by a plug of mucus. The cavity of cervix is called cervical canal which along with vagina forms the birth canal.

Vagina:
It is about 10 cm long and acts as a receptacle for the penis during copulation, for allowing menstrual flow and for serving as a birth canal during parturition. It opens to the exterior by an aperture called vaginal orifice situated posterior to the opening of urethra.

Accessory Glands:
1. A pair of greater vestibular or Bartholin’s gland occurs on each side of the vaginal orifice. They are small rounded bodies.
These glands correspond-to the Cowper’s gland of the male and secrete a clear, viscid fluid under sexual excitement. This fluid serves as a lubricant during copulation.
2. Numerous glands of skene are present on either sides of urethral orifice. They are homologous to male’s prostate and secrete mucus. These are also called lesser vestibular or paraurethral glands.

External Genitalia (Vulva):
The external genitalia of females consists of the following parts
1. Mons pubis It is the anteriormost structure of vulva and is covered with skin and pubic hairs.
2. Two longitudinal folds of tissue called labia majora form the boundary of the vulva. It also covers two additional folds of tissue called the labia minora.
Both labia majora and labia minora protect the vaginal and urethral openings.
3. Clitoris It is the small erectile organ, which lies at the upper junction of the labia minora above the urethral opening. It is a homologous structure to glans penis of males.

Frontal view of vagina with its associated structures
4. Hymen The vaginal orifice is normally covered by a membrane, called hymen. It is a thin mucous membrane, which covers the vaginal opening either partly or completely. It is often torn during the first coitus (intercourse), but may be present in some women even after coitus. Hymen may also get stretched or torn by normal activities such as horseback riding and therefore, the presence or absence is not an accurate indicator of a woman’s virginity or sexual experience.
Disorders of the Female Reproductive System

Disorder	Description
Breast cancer	Incidence increases after menopause. Signs include lump in breast, change in breast shape, fluid from nipple, etc.
Cervical	Slow growing cancer. Unnoticed until invades other tissues.
cancer	Fluid filled tumours of the ovary.
Ovarian cysts	Growth of endometrial tissue outside the uterus.
Endometriosis	Implantation of embryo at a place other than uterus.
Ectopic	Description
pregnancy	Incidence increases after menopause. Signs include lump in breast, change in breast shape, fluid from nipple, etc.

 

Question 4.
What is menstrual cycle? Describe the cycle in human with a reference to cyclic changes in the ovary and uterine endometrium.
Answer:
Menstrual Cycle:
It is the reproductive cycle in female primates, e.g. monkeys, apes and human beings.
The first menstruation begins at puberty and is called menarche. In human females, menstruation is repeated at an average interval of about 28/29 days. The menstrual cycle stops at around 50 years of age in human females and this stage is termed as menopause.

The cyclic menstruation is an indication of normal reproductive phase and extends between menarche and menopause. The cycle of events starting from one menstruation till the next one is called menstrual cycle. One ovum is released during the middle of each menstrual cycle.
The menstrual cycle consists of following four phases

Menstrual (Bleeding) Phase:
The cycle starts with menstrual phase. It lasts for about 3-5 days and involves the following events

1. If fertilisation does not occur, the unfertilised egg undergoes autolysis.
2. Reduction of LH level causes regression of corpus luteum by autolysis and thus, a consequent fall in the progesterone level occurs in the blood.
3. The endometrial lining of the uterus breaks down due to the deficiency of progesterone and is sloughed off. Blood vessels rupture, causing bleeding through vagina. The process is called menstruation or menstrual flow. It occurs only when ovum is not fertilised.

Follicular (Proliferative) Phase:
It lasts for about 14 days and involves the following events

1. The primary follicles in the ovary grow to become a fully mature Graafian follicle.
2. The endometrium of uterus regenerates through proliferation.
3. The changes in the ovary and the uterus are induced by changes in the levels of pituitary and ovarian hormones, i.e. FSH and oestrogen.
4. The secretion of gonadotropins (LH and FSH) increases gradually during the follicular phase and stimulates follicular development as well as secretion of oestrogens by the growing follicles.
   

Ovulatory Phase:
Both LH and FSH attain a peak level in the middle of cycle (about 14th day).

• Rapid secretion of LH leading to its maximum level during the midcycle is called LH surge. It induces rupture of Graafian follicle and thereby, the release of ovum, i.e. ovulation.
• The ovulation (ovulatory phase) is followed by the luteal phase.

Secretory (Luteal) Phase:
This phase lasts for about 10 days and involves the following events

1. The remaining parts of Graafian follicle transform into the corpus luteum.
2. The corpus luteum secretes large amounts of progesterone which is essential to maintain endometrium.
3. The endometrium is necessary for implantation of the fertilised ovum and other events of pregnancy. During pregnancy, all events of the menstrual cycle stop and there is no menstruation. In the absence of fertilisation, the corpus luteum degenerates.
4. This causes disintegration of endometrium, leading to menstruation.
   Only the basal part of endometrium persists, which forms the source of new lining and a new cycle starts.
   

Menstrual cycle is absent temporarily during pregnancy and lactation periods and permanently after menopause. However, it can be absent due to stress, poor health, etc. Menstruation is also called ‘weeping of uterus for the lost ovum’ or ‘funeral of unfertilised egg’. Cyclic menstruation is an indicator of normal fertility period in women. It extends from menarche to menopause.

Question 5.
Draw a neat labelled diagram of the male reproductive system in human (Description is not required).
Answer:

Question 6.
Draw a neat labelled diagram of the female reproductive system in human (Description is . not required).
Answer:

Question 7.
Draw a neat labelled diagram of the cross-section through the human ovary (Description is not required).
Answer:

Question 8.
Draw a neat labelled diagram of seminiferous tubule (Description is not required).
Answer:

Question 9.
Draw a neat labelled diagram of a Graafian follicle (Description is not required).
Answer:

Odisha State Board CHSE Odisha Class 12 Economics Solutions Chapter 10 Aggregates Related to National Incorne Questions and Answers.

CHSE Odisha 12th Class Economics Chapter 10 Question Answer Aggregates Related to National Incorne

Group – A

Short type Questions with Answers
I. Answer with in Two/Three sentence.

Question 1.
Gross National Product is always greater than Gross Domestic Product.
Answer:
Gross domestic product includes only the value of goods and services produced within the domestic territory of a country, but GNP, net factor income from abroad is another component which is added to GDP to determine GNP.

Question 2.
Net National Income is a part of gross national income.
Answer:
Net national income can be obtained by deducting value of depreciation from gross national income. So, it is a part of gross national income.

Question 3.
Personal income always exceeds disposable income.
Answer:
Disposable income is obtained by deducting direct tax from personal income. So it is a part of personal income. .

Question 4.
Output method Income method and Expenditure method are somehow similar.
Answer:
In an economy, there are three simultaneous flows i.e., output flow, income flow and expenditure flow. Thus the value of output is identical with income earned by the factors as well as the expenditure incurred.

Question 5.
Transfer payment is excluded from the computation at National Income.
Answer:
Transfer payment is made without having any productive contribution. It is exclusively meant for social security. Hence, it is not included in the national income.

Question 6.
Sale of second hand car does not constitute a part of national income?
Answer:
The amount received from the sale is not the result of any production. Rather, the production of the car has already created income which has been computed earlier. So it does not constitute a part of national income.

Question 7.
GNP at market price exceeds GNP at factor cost?
Answer:
GNP at market price is valued at prevailing price level which includes indirect tax. But GNP at factor cost is exclusive of indirect tax hence the GNP at market price is greater than GNP at factor cost.

Question 8.
Net national product is a part of the Gross National Product.
Answer:
Gross National Product is the total amount of goods & services produced in the country during a year along with the net income from abroad. Net National product is the residual of GNP left after meeting the value of depreciation & hence it is a prt of GNP.

Question 9.
Old age pension is a transfer payment.
Answer:
Transfer payment is made without having any productive contribution. As the old age pension is paid without any productive contribution, it comes under the category of transfer payment.

Question 10.
Personal income is more than the disposable income.
Answer:
Personal income is the income earned by the individual from all of his sources. But disposable income is the income left after the payment of direct tax. So it is a part of the personal income.

II. Answer with in Five/Six sentence :

(A) write short notes on :

Question 1.
National Income.
Answer:
Income is generated in the production process. Production units employ factors of production and make payment for their services. The sum total of income earned by various factors of production constitute the national income. It can, therefore, be said that national income of a country can be calculated either by taking the sum of income paid by the producing units or by the income received by the factors. In simpler words, the income method consists of the sum total of net income and payments received by the citizens of a country during a year.

In calculation of national income, according to income method, wages and salaries, compensation of employees, employers contribution towards social security, mixed income of self-employed, rent, interest, divided, surplus earning of public enterprises and net factor income from abroad are added up. The sum total of all these represent the gross national income of which net national income is apart. National income in the latter sense is arrived at by deducting the cost of depreciation from the gross national’income.

Question 2.
Gross National Product.
Answer:
Gross National product is the money value of total goods & services produced in a country during year along with the net factor income from abroad. It comprises of two aspects ; Gross domestic product at market price & net factor income from about. Thus GNP = GDP + Net factor income from abroad. In computing GNP, only the money value of final goods & services is taken into account. GNP is accepted as an indicator of economic development.

Question 3.
Domestic Income.
Answer:
Domestic income refers income earned by the factors in the domestic territory of the contry. It indicates that the income from three sectors like primary, secondary & tertiary sectors constitutes national income. All those three sector employ different factors of production which in turn, earn income. There are in form of rent, wage, interest & profit. Along with this surplus of public sector is added. With this addition, domestic income can be determined.

Question 4.
Per-capita Income.
Answer:
Per-capita income is calculated by dividing the national income by the number of people in a particular year. The per capita income may be estimated at current prices as well as constant prices. Sometimes the per capita income may not increase or may even fall if national income increase is less than the rate of increase in population. Per-capita increase in income at current prices may not present a correct picture of economic growth and standard of living in the county. Increase in per-capita income at constant prices indicates the economic growth.

Question 5.
Personal Income.
Answer:
Personal income refers to the current income of the persons or households from all sources. It includes the actual income earned by the members of the households of the economy. In order to determine the personal income the undistributed profit and tax payable should be deducted. Personal income is viewed as the aggregate of all types of factor incomes earned by the house holds.

Question 6.
Disposable income:
Answer:
The income which is left after the payment of payable tax is called disposable income. Personal disposable income is the personal income minus income tax & property taxes. Thus disposable income is that income which is left for spending. All the taxes payable & the different government obligations are deducted from the personal income so as to determine disposable income.

Question 7.
Intermediate Product.
Answer:
Intermediate products are bought and sold between producers as they are used for further production. Such goods like cotton and wheat are used for manufacture of cloth and flour respectively and as such these are called secondary inputs. The value of intermediate product is not taken into account in estimation of national income. These products remain within production boundary.

Question 8.
Transfer Payment.
Answer:
The payments which are made without having any productive contribution is called transfer payment. It is the transfer receipts like unemployment allowances, old-age pensions sickness benefits etc. These payments are made to the persons who are not rendering. Hence transfer payments are unilateral payments.

(B) Distinguish Between

Question 1.
National Income & National Product:
Answer:
National income is the factor income accruing to the normal residents of a country. It includes both domestic factor income an net factor income from abroad. National income is equal to net national product at factor cost. National product is the sum of total money value of final goods and services produced by a nation during a year. It is calculated by multiplying the quantities or different goods and services with their respective prices. The cost of depreciation, transfer payments, capital gains andi the value of intermediate goods are not taken in to account in computation of gross national income.

Question 2.
GDP&GNP:
Answer:
(i) Gross domestic product is the market value of final goods & services produced within the domestic territory during a year. But Gross national product refers to the total money value of gods & services produced in the country during a year along with the net factor income from abroad.

(ii) GDP is relatively a narrower concept & GNP is a broader concept.

(iii) Both the GD & GNP take the final goods & services into account & ignores the intermediate goods.

Question 3.
National income & Personal Income :
Answer:
National Income refers to the income of the country as a whole whereas personal income is the income received by the individuals or house holds. National income is a broader cohcept but personal income is a narrower concept. The sum of personal incomes becomes a form of national income. Personal income is never equal to national income. Thus national has several components which are most in the personal income.

Question 4.
Intermediate goods & final goods:
Answer: Intermediate goods are those goods Which are used for further production. But final goods are meant for direct consumption. Intermediate goods are generally preducers goods that

provide indirect satisfaction to the consumer whereas the final goods provide the direct satisfaction to the consumer. In case of national income accounting, the money value of final goods is taken into consideration & the value of intermediate gods is deducted in national income accounting. It is very difficult to treat one good as intermediate or final goods.

Question 5.
National income in constant price and current price.
Answer:
National income may be calculated at current and constant prices. The value of goods and services measured at base year prices is called national income at constant prices. When goods and services are valued at prevailing prices of a particular year the national income at current price. Since prices have a tendency to rise in modem times national income is valued at current price does not indicate the actual growth of an economy. National income at constant price reveals the real national income and the standard of living of the people.

Question 6.
Personal income and disposable income.
Answer:
Personal income is the current income received by persons from all sources including transfer income from government and business. It includes direct taxes. Disposable income refers to that part of personal income which an individual can spend or save. Disposable income is arrived at by deducting all taxes from personal income.

Group – B

Long Type Questions With Answers

Question 1.
What is National Income ? What are its related concepts?
Answer:
The concept ‘National income’ has been defined in a number of ways. However the definitions of national income can be grouped under two heads, namely the traditional definition and modem definition.

The traditional definition was advanced by Alfred Marshall, A.C. Pigou and Fisher. According to Marshall, “The labour and capital of a country acting on its natural resources, produce annually a certain net aggregate of commodities material and non-material including services of all kinds…. this is the true net annual income or revenue of the country or national devidend.”

According to Pigou, “National income is that part of objective income of the community, including of course income derived from abroad which can be measured in money.” According to Central Statistical Organisation, “national income is the sum of factor income earned by the normal residents of a country in the form of wages, rent, interest and profit in an accounting year.”

However, national income may be defined as the sum of factor incomes, viz., wages, rent, interest and profit accming to the normal residents of a country for their productive activities during a definite period of time, say a year. National income refers to the sum of the factor rewards, namely wages, rent, interest and profit accruing to the citizens of a country for their productive activities during a year.

National product refers to the sum of the market value of final goods and services produced by the citizens of a country during a year. National expenditure refers to the sum of expenditures on consumption investment, government purchase of goods and services, and net foreign investment.

There are various related concepts of national income. These are explained below :
1. Gross Domestic Product at Market Price : Gross domestic product at market price is defined as the market value of the final goods and services produced by all the producers in the domestic territory of a country during an accounting year. Thus, Gross Domestic Product at Market Price = Value of output in domestic territory – value of intermediate consumption. GDP at market price can also be calculated by adding net indirect taxes to GDP at factor cost i.e.; GDP at market prices = GDP at factor cost + Net indirect taxes.

2. Net domstic Product at Market Price : Net domestic product at market price is the market value of final goods and services produced by all the producers in the domestic territory of a country during an accounting year exclusive of consumption of fixed capital. It is equal to the net value added at market price. Thus the net domestic product at market price includes all those items which are included in gross domestic product at market price except the consumption of fixed capital. So, Net Domestic Product at Market Price = Gross Domestic Product at Market Price – consumption of Fixed Capital.

3. Gross National Product at Market Price : Gross national product at market price is defined as the market value of the final goods and services produced in the domestic territory of a country by normal residents during an accounting year including net factor, income from abroad. Thus gross national product at market price includes all the constituents of gross domestic product at market price and net factor income from abroad. In other words, Gross National Product at Market Price = Domestic Product at Market Price + Net Factor-Income abroad.

4. Net National Product at market Price : Net national product at market price is the market value of the final goods and services produced by normal residents of an economy in its domestic territory during an accounting year exclusive of depreciation and inclusive of net factor income abroad. Net national product at market price is nothing but gross national product at market price less consumption of fixed capital or depreciation. Thus, Net National Product at Market Price = Gross National Product at Market Price – Consumption of fixed Capital (depreciation).

5. Gross Domestic Product at Factor Cost: Gross domestic product at factor cost or gross domestic income is the sum of net values added by all the producers in the domestic territory of the country and the value of consumption of fixed capital during an accounting year. Thus, gross domestic product at factor cost is the sum of net value added by all the producers in the domestic territory of the country and the consumtion of fixed capital. As such,
Gross Domestic Product at Factor Cost = Sum of net values added + consumption of fixed capital.
Similarly,
Gross Domestic Product at factor cost = Gross Domestic factor income + consumption of fixed capital.

Gross Domestic Product at factor cost can also be estimated by deducting net indirect taxes from gross domestic product at market price. As such,
Gross Domestic Product at factor cost = Gross Domestic Product at Market Price – Net Indirect taxes.

6. Net Domestic Product at Factor Cost: Net domestic product at factor cost is nothing but gross domestic product at factor cost less depreciation. As such,
Net Domestic Product at Factor Cost = Gross Domestic product at factor cost – Depreciation.

Net domestic product at factor cost can also be estimated by deducting net indirect taxes from net domestic product at market price.
As such,
Net Domestic Product at factor Cost = Net Domestic Product at Market Price – Net Indirect taxes.

7. Gross National Product at Factor Cost: Gross National Product at factor cost is the difference between gross national product at market price and net indirect taxes. It is also called gross national income. It is nothing but the sum of domestic factor income and net factor income from abroad. According to Peterson, “Gross National Product at factor cost is the sum of gross value added at factor cost by the normal residents of the country during a year and net factor income from abroad.

Gross National Product at Factor cost = Gross Domestic Product at factor cost + Net factor income from abroad.
Similarly,
Gross National Product at factor cost can also be calculated by deducting net indirect taxes from gross national product at market price.
GNP at factor cost = Net national product at factor cost + Depreciation.

Gross National Product at factor cost can also be calculated by deducting net indirect taxes from gross national product at market price.
Gross National Product at Factor cost = Gross National Product at Market Price – Net Indirect Taxes.

8. Net National Product at Factor Cost: Net National Product at factor cost is the sum of net value added at factor cost by normal residents in the domestic territory of a country and net factor income from abroad in an accounting year. Net national product at factor cost is nothing but gross national product at factor cost less depreciation or consumption of fixed capital. As such.

Net National Product at Factor Cost = Gross National Product at factor cost – Depreciation.
Net national product at factor cost can also be calculated by the sum of net domestic product, at factor cost and net factor income from abroad. As such,
Net National Product at Factor Cost = Net Domestic Product at Factor Cost + Net Factor Income from Abroad.

Net national product at factor cost can also be calculated by deducting net indirect taxes from net national product at market price. As such,
Net National Product at factor cost = Net National Product at Market Price – Net Indirect taxes.

Net national product at factor cost is equal to national income. Two points have to be carefully noted :
(i) the difference between gross and net agregates is the value of consumption of fixed capital, and
(ii) the difference between market prices and factor cost is the value of net indirect taxes.

Question 2.
Describe the income method for calculation of National Income.
Answer:
National income refers to the money value of all goods & services produced in the country during a particular year along with the net income from abroad. In other words, it is conceived as sum of all factor incomes earned by the different factors during a particular year to measure the national income, generally three methods like Income method, expenditre method & output method are adopted.

Income Method : In income method, the factor incomes like rent, wage, interest & profit are added together to defermine the national income in a particular year. In other words, the rewards to land-lords, labourers, capitalists & entrupreneurs are added together. It is a fact that the production of goods & services generates income simultaneously which is equal to the value of the product. So by adding up rent, wage, interest & profit, national income can be found out.

To find out national income, just two sectors like private sectors & Govt, sectors are considered & in open economy, the net income from abroad is added to the income of these two sectors. Thus, according to income method, the income accruing to private sector, government sector & foreign sector are added. So, calculation of national income under income method covers up domestic sector (Private sector & Public Sector) & foreign sector.

Income from domestic sector : Domestic income refers income earned by the factors in the domestic territory of the contry. It indicates that the income from three sectors like primary, secondary & tertiary sectors constitutes national income. All those three sector employ different factors of production which in turn, earn income. There are in form of rent, wage, interest & profit. Along with this surplus of public sector is added. With this addition, domestic income can be determined.

Income from Foreign Sector : Anoter constituent of national income is the income from foreign sectors. It is expressed as Net Factor Income from Fbroad. In an open economy, certain factors of the country may be employed in foreign countries which earn income. Besides, in the process of international trade, there may emerge certain net exports. All these become a part of national income & hence added to the domestic income of calculate the national income. Thus,
National Income = Domestic Income + Net Factor income from Abroad.

Precautions : In income method, some precautionary measures are taken while calculating national Income. There are mentioned below:
(a) Value of the goods used by the producer or income from the self owned land, (rent), from the self-management wage), from the self invested capital (interust) should be carefully taken into consideration.

(b) Transfer income which is paid without having any productive contribution must be deducted.

(c) Black Moey & Income from illegal sources should not be considered.

(d) Public debts incurred in unproductive purpose is not included in national income. With all these precautions, national income can be calculated. But, this method can not alone determine the national income correctly.

Question 3.
Explain the expenditure method for the estimation of National Income.
Answer:
Expenditure method is also used to measure national income. In this method final expenditure on gross domestic product is taken into account. Expenditure on final consumption of goods is called final consumption expenditure, government final consumption expenditure, gross captial formation (investment), change in stock and net exports. Households and general government make purchases of goods and services in the market for final consumption.

Household enterprises and general government purchase capital goods for replacement of worn out parts. Government and consumer households make purchase from outside the country which is termed as imports. Similarly domestic goods and services are sold outside the country which is termed as imports. Similarly domestic goods and services are sold outside the country which is called exports. The difference between value of exports and the value of imports constitutes the net exports which form part of expenditure on gross domestic product.

To measure the final expenditure on gross domestic product, it is necessary to ascertain the retail price and quantity of goods and services, by to the household and private non-profit organisations the final consumption expenditure is known. Resident households also make direct purchases abroad. Expenditure on this account has to be added to final consumption expenditure. Non-resideni households make direct purchases in the domestic market which has to be deducted from therate final consumption expenditue.

The final consumption expenditure of the government is known by adding the net purchases of goods and services by the government and payment made as compensation of employees. By multiplying the quantity of sales with the retail price the expenditure of the government in the domestic market is known. Government also makes purchases from abroad. Thus by adding the government’s expenditure on purchases in the domestic market, purchases from abroad and compensation of employees the final consumption expenditure of the government is arrived at.

The next item is gross fixed capital formation. Capital formation refers to excess of production over consumption during a year. Capital formation takes places in shape of gross fixed capital formation and change in stocks. Expenditure on these two accounts show the total expenditure on gross capital formation. Gross fixed capital formation consists of construction and acquisition of machinery and equipment. Expenditure on construction can be found out by multiplying the price of exports with the volume of inputs used plus compensation of employees’ rent, interest and profits. Care should be taken to include own account productional of fixed assets, purchase of new houses by households, work in progress and renovation of old buildings in the final expenditure.

Similarly, final expenditure on machinery and equipment is found out by multiplying the quantity of machinery and equipment produced during the year with the market price. The value of own account production is added to the expenditure. As regards expenditure on change in stocks, the physical change in stocks in multiplied with the market prices. The total expenditure on gross capital formation is thus, arrived at by adding expenditure on gross fixed capital and change in stocks of the domestically produced goods and services.

The next item to be considered is net exports. Net exports is the difference between the exports and imports during a year. Expenditure on net exports forms a part of expenditure on gross domestic product.

While estimating national income on the basis expenditure method care should be taken not to include expenditure on the second-hand goods, expenditure on purchase of shares, debentures and bonds, transfer payments like pensions, unemployment allowances and contribution to social security schemes. Cost of intermediate goods etc. However, the value of products for self consumption expenditure. Similarly expenditure on imputed rent of the owner occupied houses is also included in the final consumption expenditure.

The expenditure method sugggests the gross domestic product at market prices. The .gross national product at market prices is arrived at by adding net factor income from abroad to the gross domestic product. The net national product at factor cost which is same as national income is arrived at by deducting net indirect taxes and the cost of depreciation from the gross national product.

Difficulties in expenditure method : Measurement of national income through expenditure method, though appears, simple, is beset with certain practical difficulties. First of all, expenditure method will deliver correct information, provided correct data ar available. Generally, data on expenditure, at different stages are not fully available. As a result, there is liselhood of underestimation of national income. Similarly national figures may be exaggerated of double counting is not avoided.

Secondly, in case of consumer durables it is difficult to distinguish between consumption expenditure and investment expenditure. Such goods render services over a long period of time. In such cases it is difficult to measure the value of services rendered every year and include the same in the expenditure of a particular year.

Thirdly, some times, it is difficult to differentiate between consumption expenditure and investment expenditure of the Government. For example, defence expenditure is treated as consumption whereas expenditure on infrastructure development is considered as investment expenditure. Lastly, a correct picture of change in stock may not be available for the purpose of national income calculation.

Question 4.
Describe the product method (output method) for the calculation of National Income.
Answer:
Product method is a method which measures the national income by estimating the contribution of each producing enterprise to production in the domestic territory of the country in an accounting year. Product method is also known as value added method of net output method or industrial origin method. The measurement of national income using product method involves the following steps.

The first step of this method involves in identifying all those producing enterprises which employ factor inputs. All the producing enterprises are broadly classified into the following three industrial sectors.

(a) Primary Sector: Primary sector is that sector which produces goods by exploiting natural resources. The sector including agriculture and allied activities like fishing, mining and quarrying. All these sub sectors produce goods by exploiting natural resources like land, water, forests mines, etc.

(b) Secondary Sector : Secondary sector is one in which the enterprises trasform one type of commodity into another type of commodity, e.g., manufacturing cloth from cotton, sugar from sugarcane, etc. This is also called manufacturing sector.

(c) Tertiary Sector : Tertiary sector is one in which the enterprises produce services only, such as banking, insurance, transport, communications, trade, commerce, etc. this sector is also known as service sector.

The second step of this method involves in the estimation of net value added. In this connection, values of certain parameters like value of output, value of intermediate consumption and consumption of fixed capital, need to be estimated.

Estimating value of output across primary, secondary and tertiary sectors of the economy involves its own problems. In fact, one may estimate value of output using two different techniques or methods. These are final output method and value added method.

According to final output method, the value of output is estimated as the sum of sales and change in stock of the producing units. Value of output thus estimated should not be taken to mean as the value of final output. Value of output includes the value of final goods as well as the value of intermediate goods, while the value of final output refers to the value of final goods and services in isolation from the value of intermediate consumption. Thus final output is estimated as the difference between the value of total output and intermediate consumption. Thus, value of final output = Value of total output – Intermediate consumption. Using this method one might encounter the problem of double counting.

According to the value added method, each producing unit of the economy is required to furnish data not on the value of output but on value added which is estimated as the difference between value of output and intermediate consumption, thus, value added = Value of output – Intermediate consumption. Value added obviously refers to the value of final goods and services produced by each producing unit of the country. We get domestic product at market price by adding ‘value added’ of all the producing units within the domestic territory. Thus the method of value added is preferable to the method of final output in estimating national income.

The final step is the estimation of national income. Gross value added by all the producing units across three sectors of the economy is added up to obtain gross domestic product at market price. Consumption of fixed capital or the value of depreciation is deducted from gross value added at market price to obtain net value added at market price or net domestic product at market price.

Net indirect taxes may be deducted from net domestic product at market-price in order to obtain net domestic product at factor cost or net value added at factor cost. It is also called net domestic income. By adding net factor income from abroad to net domestic product at factor cost we get net national product at factor cost or national income.

Precautions regarding value Added Method:

While estimating national income through value added method, following important precautions must be taken.

1. Value of the sale and purchase of second hand goods is not included in value added.
2. Commission earned on accounting of the sale and purchase of second hand goods is included in the estimation of value added.
3. Own-account production of goods of the producing units is taken into account while estimating value added.
4. Value of intermediate goods is not included in the estimation of value added.
5. Imputed value of production for self-consumption is taken into account.
6. Imputed rent on the owner occupied house is also taken into account.
7. Production of services for self-consumption is not considered while estimating value added.
8. The value added method gives us the domestic product only. The national product is calculated by adding net factor income from abroad.
9. The value added in the government sector is equal to compensation of employees. It is because the data regarding rent and interest are not available in this sector, and profit does not exist because all that is produced is meant for collective consumption, and is not sold in the market.

Group – C

Objective type Questions with Answers
I. Multiple Choice Questions with Answers :

Question 1.
The value of goods & services produced within the territory of a country is known as
(i) GNP
(ii) GDP
(iii) NNP
(iv) None of the above
Answer:
(ii) GDP

Question 2.
GDP becomes equals to GNP if
(i) Depreciation is added
(ii) import is added
(iii) export is added
(iv) net export is added
Answer:
(iv) net export is added

Question 3.
The money value of national product produced during a year is known as
(i) GNP
(ii) National income
(iii) GDP
(iv) NNP
Answer:
(iii) GDP

Question 4.
The physical quantities of goods multiplied with prevailing price level gives rise to
(i) national income at current price
(ii) national income at constant price
(iii) per capital income
(iv) Both (i) and (ii)
Answer:
(i) national income at current price

Question 5.
If national income of a country increases in proportion to increase in population, the per capital income.
(i) increases
(ii) decreases
(iii) remains same
(iv) none of the above
Answer:
(iii) remains same

Question 6.
Average income of the people in the country is termed as
(i) per capital income
(ii) national income
(iii) net national income
(iv) average real income
Answer:
(i) per capital income

Question 7.
Which is the element that influences the per capital income?
(i) population of the country
(ii) national income
(iii) GNP
(iv) Both (i) and (ii)
Answer:
(iv) Both (i) and (ii)

Question 8.
The goods which are not meant for production nor for resale is called
(i) intermediate goods
(ii) final goods
(iii) goods for self consumption
(iv) All of the above
Answer:
(ii) final goods

Question 9.
The goods which are exchanged between the producers are
(i) final goods
(ii) consumer goods
(iii) intermediate goods
(iv) all of the above
Answer:
(iii) intermediate goods

Question 10.
Which is not the element of domestic factor income?
(i) compensation of employees
(ii) operating surplus
(iii) mixed income
(iv) net income from abroad
Answer:
(iv) net income from abroad

Question 11.
Which is not included in compensation of employees.
(i) salaries
(ii) wages
(iii) travelling allwance
(iv) insurance premium of workers
Answer:
(iii) travelling allwance

Question 12.
Which is not included in operating surplus?
(i) Rent
(ii) wage
(iii) interest
(iv) profit
Answer:
(ii) wage

Question 13.
The income of self-employed individuals is called
(i) mixed income
(ii) operating surplus
(iii) compensation of employees
(iv) income of individuals
Answer:
(i) mixed income

Question 14.
Old age pension is included in
(i) compensation of employees
(ii) mixed incon
(iii) transfer payments
(iv) operating surplus
Answer:
(iii) transfer payments

Question 15.
Which is included as transfer payments?
(i) old age pensions
(ii) gifts
(iv) all of the above
(iii) donations
Answer:
(iv) all of the above

Question 16.
Which is not included in private income?
(i) profit of public undertakings
(ii) transfer payments
(iii) “net factor income from abroad
(iv) interest on national debt.
Answer:
(i) profit of public undertakings

Question 17.
Which is not included inn personal income?
(i) salary
(ii) wage
(iii) transfer payment
(iv) saving
Answer:
(iv) saving

Question 18.
Disposable income is the personal income left after debucting
(i) direct tax
(ii) indirect tax
(iii) subsidy
(iv) interest on debt
Answer:
(i) direct tax

Question 19.
Which is included in compensation of employees
(i) bonus
(ii) dearness allowance
(iii) sick leave allowance
(iv) all of the above
Answer:
(iv) all of the above

Question 20.
In which category insurance premium & provident fund contribution are included
(i) mixed income
(ii) operating surplus
(iii) compensation of employees
(iv) personal income
Answer:
(iii) compensation of employees

Question 21.
Royalties are included in
(i) mixed income
(ii) operating surplus
(iii) disposable income
(iv) private income
Answer:
(ii) operating surplus

Question 22.
The income received by the lawyers, doctors etc are
(i) personal income
(ii) disposable income
(iii) private income
(iv) mixed income
Answer:
(iv) mixed income

Question 23.
The output method used for measuring national income is otherwise known as
(i) income method
(ii) value added method
(iii) expenditure method
(iv) both (i) and (ii)
Answer:
(iii) expenditure method

Question 24.
The common difficulty taken place in measuring national income is
(i) double counting
(ii) selection of price
(iii) distinction between quantum of final goods & intermediate goods
(iv) all of the above
Answer:
(iv) all of the above

Question 25.
Which income is not counted in measuring national income?
(i) transfer payments
(ii) income from second hand sale
(iii) income from robbery
(iv) all of the above
Answer:
(iv) all of the above

Question 26.
Which tax should not be included in national income?
(i) wealth tax
(ii) estate duty
(iii) gift tax
(iv) all of the above
Answer:
(iv) all of the above

Question 27.
Undistributed profit is an element of:
(i) Personal income
(ii) Private income
(iii) National income
(iv) None of the above
Answer:
(ii) Private income

Question 28.
Personal income is more than :
(i) Personal disposable income
(ii) Private income
(iii) All of the above
(iv) None of the above
Answer:
(i) Personal disposable income

Question 29.
An example of operating surplus is:
(i) wage of salary
(ii) Rent or interest
(iii) Firms and household
(iv) None of the above
Answer:
(ii) Rent or interest

Question 30.
Mixed income earned by :
(i) An industrialist
(ii) A self employed
(iii) All of the above
(iv) None of the above
Answer:
(ii) A self employed

Question 31.
Under expenditure method, National Income is measured at:
(i) Cost price
(ii) Market price
(iii) Both A and B
(iv) None of the above
Answer:
(ii) Market price

Question 32.
G D. P. is the collective effort of:
(i) Domestic factors
(ii) Both domestic and foreign factors
(iii) Foreign factos
(iv) All of the above
Answer:
(ii) Both domestic and foreign factors

Question 33.
G. N. P. at factor cost is equal to :
(i) G N. P. at market price – Net indirect taxes
(ii) G N. P. at factor cost + Net indirect taxes
(iii) G N. P. at cost factor cost – Depreciation
(iv) None of the above
Answer:
(i) G N. P. at market price – Net indirect taxes

Question 34.
G N. Pat factor cost is :
(i) Net national product at factor cost – depreciation
(ii) Net national product at factor cost + depreciation.
(iii) G. N. P. at factor cost + depreciation
(iv) None of the above
Answer:
(ii) Net national product at factor cost + depreciation.

Question 35.
Net national product at factor cost is
(i) G N. P. at factor cost + Depreciation
(ii) G N. P. at factor cost – Depreciation
(iii) G N. P. at factor cost – Net indirect taxes
(iv) None of the above
Answer:
(ii) G N. P. at factor cost – Depreciation

Question 36.
Interest paid on public debt is a :
(i) Factor payment
(ii) Transfer payment
(iii) Capital payment
(iv) None of the above
Answer:
(ii) Transfer payment

II. Fill in the blanks :

Question 1.
_____ refers to the income accruing from property and from work of self-employed persons.
Answer:
Mixed income

Question 2.
_____ is that part of profit of a firm which is distributed among the share-holders.
Answer:
Dividend

Question 3.
Indirect taxes are not included in national income as it is not a _____ income.
Answer:
Factor

Question 4.
_____ income being an unilateral payment falls outside generated income.
Answer:
Transfer

Question 5.
National product of country becomes lesser than the domestic product when net factor income from abroad is _____ .
Answer:
negative

Question 6.
Capital transfers are met from _____ savings.
Answer:
Past

Question 7.
Personal disposable income excludes _____ taxes.
Answer:
Direct

Question 8.
Interest on public debt is a _____ payment.
Answer:
Transfer

Question 9.
Pension is _____ a income.
Answer:
Transfer

Question 10.
Old age pension is an example of _____ payment.
Answer:
Transfer

Question 11.
Real percapita income is measured in _____ price.
Answer:
Constant .

Question 12.
Income earn by the factor of production is _____ at factor cost.
Answer:
Net National Product

Question 13.
Disposal income is a part of _____ income.
Answer:
Personal

Question 14.
The income earned by the self employed person is _____ income.
Answer:
Mixed .

Question 15.
_____ is deducted from the personal income so as to get disposable income.
Answer:
Direct tax .

Question 16.
The average annual income of the residents of a country is called _____.
Answer:
Percapita income

Question 17.
increase in _____ income indicates economic growth of a country.
Answer:
Real percapita income

Question 18.
Expenditure for the advertisement is a part of _____ consumption.
Answer:
Interview

Question 19.
_____ goods is accepted for the estimation of National income.
Answer:
Final good.

Question 20.
The income cam by a lawer is _____ income.
Answer:
Mixed

III. Correct the Sentences:

Question 1.
National income is the value of goods & services produced in the country during a year.
Answer:
Incorrect.
Correct – National income is the value of goods & services produced in the country during a year including the net income from abroad.

Question 2.
Gross Domestic product is greater than Gross national product.
Answer:
Incorrect.
Correct – Gross Domestic product is less than Gross national product.

Question 3.
National income is calculated for a particular year.
Answer:
Correct.

Question 4.
GNP at market price is less than GNP at factor cost.
Answer:
Incorrect.
Correct – GNP at factor cost is less than GNP at market price.

Question 5.
GDP at market price = GDP at factor cost – Net Indirect Tax.
Answer:
Incorrect.
Correct – GDP at market Price = GDP at factor cost + Net Indirect Tax.

Question 6.
The difference between market prices & factor cost is the net income from abroad.
Answer:
Incorrect.
Correct – The difference between market prices & factor cost is the net indirect tax.

Question 7.
Net aggregates are always greater than gross aggregates.
Answer:
Incorrect.
Correct – Net aggregates are always less than gross aggregates.

Question 8.
Private income is less than personal income.
Answer:
Incorrect.
Correct – Private income is greater than personal income.

Question 9.
Personal income is less than disposable income.
Answer:
Incorrect.
Correct – Personal income is greater -than disposable income.

Question 10.
Personal income is the sum of all types of factor income.
Answer:
Correct.

Question 11.
Disposable income = Personal income – indirect tax.
Answer:
Incorrect.
Correct – Disposable income = Personal income – direct tax.

Question 12.
Undistributed profits are the savings of house hold.
Answer:
Incorrect.
Correct – Undistributed profits are the savings of the enterprises.

Question 13.
Product method is called output method.
Answer:
Correct.

Question 14.
The value of final goods are added in product method to calculate national income.
Answer:
Incorrect.
Correct – The value of final goods are added in product method to calculate national incoem.

Question 15.
The value of intermediate consumption is added to the value of final goods to calculate national income.
Answer:
Incorrect.
Correct – The value of intermediate consumption is deducted from the value of final goods to calculate national income.

Question 16.
Income method is value added method.
Answer: Incorrect.
Correct – Product method is value added method.

Question 17.
Factor incomes are added in the income method for estimating national income.
Answer: Incorrect.
Correct – Factor incomes are added in the income method for estimating national income.

Question 18.
Operating surplus includes the income of self employed persons.
Answer: Incorrect.
Correct – Operating surplus includes income from property & entrepreneurship.

Question 19.
Rent is an operating surplus.
Answer: Correct.

Question 20.
Salaries & wages are the mixed income.
Answer:
Incorrect.
Correct – Salaries & wages are compensation of employees.

Question 21.
Old age pension is a transfer income.
Answer: Correct.

Question 22.
Incomes of the self employed person is an operating surplus.
Answer:
Incorrect.
Correct – Incomes of the self employed person is mixed income.

Question 23.
National product is greater than national income.
Answer:
Incorrect.
Correct – National product is equal to national income.

Question 24.
GNP is greater than NNP.
Answer:
Correct.

Question 25.
Operating surplus does not occur in government sector.
Answer:
Correct.

II. Answer the following questions in one word :

Question 1.
What is National Income?
Answer:
National income refers to the money value of total goods & services produced during a year alongwith net income from abroad.

Question 2.
What is GNP?
Answer:
GNP refers to the total volume of goods & services produced during a year along with the net exports.

Question 3.
How can be Net National Product be found, out?
Answer:
GNP – value of depreciation = NNP.

Question 4.
What is Gross Domestic Product?
Answer:
Gross Domestic Product is the market value of all final goods & services produced within the domestic territory of a counry during a year.

Question 5.
What is Private Income?
Answer:
Private income refers to the income of Private individuals from all the sources.

Question 6.
What is Personal Income?
Answer:
Personal Income refers to the income received by the individual from all sources.

Question 7.
What is disposable income?
Answer:
The income which can be spent on consumption by the individuals is called disposable income.

Question 8.
What is per capita income?
Answer:
Percapita income is an average income of an indiviudual in a particular year.

Question 9.
What is Product method?
Answer:
Product method is a method adopted for measuring the national income by estimating the contribution of each producing enterprise to production during a year.

Question 10.
Which method is called value-added method?
Answer:
Product method is called value-added method.

Question 11.
What is income method?
Answer:
Income method is adopted for measurin national income by adding the factor incomes like rent, wage, interest & profit during a particular year.

Question 12.
What is operating surplus?
Answer:
The operating surplus includes income from property & entrepreneurship.

Question 13.
What are the examples of operating surplus?
Answer:
Rent, interest, profit etc. are the examples of operating surplus.

Question 14.
What is transfer income?
Answer:
The income which is earned without any productive contribution is called transfer income.

Question 15.
What is compensation of employees?
Answer:
The compensation of employees includes wages & salaries in cash & inland, payment for social csecurity etc.

Question 16.
What is mixed income?
Answer:
Mixed income refers to the incomes of the self employed persons.

Question 17.
What is expenditure method?
Answer:
Expenditure method measures the national income by adding final expenditure on GDP at market price dring a year.

Question 18.
What is transfer income?
Answer:
The income which is earned without any productive contribution is called transfer income.

Question 19.
What is value added method ?
Answer:
Value added method is a method for the estimation of national income in which the national income is calculated by adding the value of final goods & services produced in an economy during a year.

Question 20.
What is intermediate goods?
Answer:
The goods which are used for further production is called intermediate goods.

Question 21.
Give an example of transfer payment.
Answer:
Old age pension.

Question 22.
What is net exports?
Answer:
The difference between the value of exports & imports is called net exports.

Odisha State Board CHSE Odisha Class 12 Biology Solutions Chapter 2 Sexual Reproduction in Flowering Plants Textbook Questions and Answers.

CHSE Odisha 12th Class Biology Chapter 2 Question Answer Sexual Reproduction in Flowering Plants

Sexual Reproduction in Flowering Plants Class 12 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Fill in the blanks with correct answer from the choices given in the bracket

Question 1.
When gynoecium matures first it is called ………… to effect cross-pollination. (protogyny, protandry, herkogamy, unisexuality)
Answer:
protogyny

Question 2.
In ornithophily, the agents for cross-pollination are ………….. . (ants, birds, snails, rats)
Answer:
birds

Question 3.
Zygote develops from …………. cell of the embryo sac. (egg, synergid, antipodal, nucellus)
Answer:
egg

Question 4.
Fertilisation was discovered by …………. (Strasburger, Mendel, Nitsch, Bower)
Answer:
Strasburger

Question 5.
Due to triple fusion, ……….. is formed.
(zygote, embryo, endosperm, zoospore)
Answer:
endosperm

Question 6.
The innermost layer of wall layers is ………….. (tapetum, epidermis, endodermis, endothecium)
Answer:
tapetum

Question 7.
Straight ovules are called ……………… (anatropous, campylotropous, orthotropous, hemitropous)
Answer:
orthotropous

Question 8.
Contrivance of self-pollination is ………….. (dicliny, herkogamy, self-sterility, cleistogamy)
Answer:
cleistogamy

Answer each of the following in one word or more words

Question 9.
Androecium and gynoecium whorls are present in the same flower.
Answer:
Bisexual flower

Question 10.
Both the essential whorls are absent in a flower.
Answer:
Neuter flower

Question 11.
Petals are united in a flower.
Answer:
Gamopetalous

Question 12.
Free carpels in a flower.
Answer:
Apocarpous

Question 13.
Transfer of pollen grains from anther to stigma of the same flower.
Answer:
Self-pollination

Question 14.
The process in which the’male gamete fertilises with egg.
Answer:
Fertilisation

Question 15.
Pollination in aquatic plants.
Answer:
Hydrophily

Question 16.
Fusion of one male gamete with definitive nucleus.
Answer:
Triple fusion

Correct the statements without changing underlined words only

Question 17.
Anemophilous flowers are pollinated by ants.
Answer:
Anemophilous flowers are pollinated by wind.

Question 18.
Dichogamy is found in bisexual flowers where stamens and carpels mature at same time.
Answer:
Dichogamy is found in bisexual flowers where stamens. and carpels mature at different time.

Question 19.
The ovule is attached to the placenta of ovary by means of nucellus.
Answer:
The ovule is attached to the placenta of ovary by means of a stalk called funiculus.

Question 20.
Animals acting as agents of pollination are called anemophily.
Answer:
Animals acting as agents of pollination are called zoophily.

Question 21.
Polyembryony involves development of one embryo.
Answer:
Polyembryony involves development of more than one embryo from a single fertilised ovum.

Fill in the blanks

Question 22.
The cells present on two sides of egg in the egg apparatus are called ……………..
Answer:
synergids

Question 23.
The outer wall of the pollen grain is called …………..
Answer:
exine

Question 24.
The male gametes are formed from …………. cell.
Answer:
generative

Question 25.
Parthenogenesis means development of fruits without ……………….
Answer:
fertilisation

Question 26.
The endosperm in which first division is cellular and subsequential cellular is called ……………… endosperm.
Answer:
cellular

Question 27.
In grafting, the part of the plant detached is called ………….
Answer:
scion

Question 28.
In self-pollination, pollen is transferred to stigma of the ………….. flower.
Answer:
same

Question 29.
The fertile cells from which microspores or megaspores developed are called ………….. cells.
Answer:
diploid mother

Question 30.
In maize plant, male inflorescence is borne at portion of the plant.
Answer:
tassel

Question 31.
The fusion product of male gamete and egg cell in angiosperms form …………….
Answer:
zygote

Short Answer Type Questions

Write notes on the following with at least 2 valid points

Question 1.
Parthenogenesis
Answer:
The word parthenogenesis is derived from two Greek words, parthenos means ‘virgin’ and genesis means ‘origin’. It can be defined as the formation of embryo from an unfertilised egg or female gamete. In plants, parthenogenesis is a component process of apomixis.
In parthenogenesis, the haploid egg in which no ‘ fertilisation occurs, develop into an embryo. This forms – viable seed which can give rise to a new plant. In , contrast, in parthenocarpy if seeds develop, they are abortive and do not give rise to new plants.

Question 2.
Allogamy
Answer:
Cross-pollination is also called allogamy. It is the transfer of pollen grains from anther of flower to stigma of flower on another plant of same or allied species.

Question 3.
Herkogamy
Answer:
Herkogamy is seen in orchids where male or female sex organs themselves prove as a barrier to prevent self-pollination by some structural abnormalities.

Question 4.
Geitonogamy
Answer:
It is a kind of pollination where the pollen grains from the anther of a flower are transferred to the stigma of another flower borne on the same plant but at different branches. It usually occurs in plants which show monoecious condition, e.g. Cucurbita. It is functionally a type of cross-pollination (involving a pollinating agent), but genetically it is similar to autogamy (since pollen grains come from same plant).

Adaptations (Contrivances) for Self-Pollination
The contrivances of self-pollination include homogamy, dichogamy and cleistogamy.

• Homogamy In this condition, both anther and stigma mature at the same time, e.g. Mirabilis.
• Dichogamy In this condition, anther and stigma mature at different times, e.g. sunflower.
• Cleistogamy The flowers which are always closed are known as deistogamous, e.g. Oxalic
  

Advantages of SeLf-PoLlination

• Fertilisation and production of the progeny are always certain by this method.
• It maintains purity of race and superiority of the variety.
• Here there is less wastage of pollens.

Disadvantages of SeLf-Pollination

• It leads to loss of viability and vigour of the plant in the long run.
• If lethal genes become homozygous, the effect may be disastrous.

Question 5.
Xenogamy
Answer:
Cross-pollination within a species (different variety) is called xenogamy and it results in production of hybrids.

Question 6.
Self-sterility
Answer:
Self-incompatibility or Self-sterility is the third device to prevent inbreeding. It is a genetic phenomenon of preventing the pollen from fertiismg ovules by the same flower by inhibiting pollen germination or pollen tube growth în the pistil.
Self-incompatibility may be due to genotype of sporophyte known as sporophytic incompatability whereas if it is due to genotype of pollen, it is known as gametophytic incomparibility.

Question 7.
Entomophily
Answer:
Pollination taking place under water is known as hypohydrogamous whereas pollination taking place on surface of water is cailed epihydrogamous.

Question 8.
Embryo sac
Answer:
Embryo sac refers to female gametophyte of a plant.
Organisation of Female Gametophyte (Embryo Sac)
In general, the development of embryo sac is monosporic, e.g. in Polygonum. In this type of development, only one megaspore situated towards chalazal end remains functional, while the remaining three megaspores gradually degenerate and finally disappear. Following are the different stages in development of female gametophyte

1. The functional haploid megaspore is the first cell of female gametophyte of angiosperm.
2. It enlarges in size to form the female gametophyte, also called embryo sac.
3. Its nucleus undergoes mitotic division to form 2-nuclei that move to opposite poles forming 2-nucIeate embryo sac.
4. The 2-nucleate embryo sac undergoes two more sequential mitotic divisions giving rise to the 4-nucleate stage and later 8-nucleate stage of embryo sac. This stage comprises of a micropylar end and a chalazal end with four nuclei at each end.
5. Six of the eight nuclei are surrounded by cell walls and get organised into cells. Three cells present towards the micropylar end grouped together, constitute the egg apparatus, i.e. two synergids and one egg cell.
6. Three cells of the chalazal end are called the antipodals. The large central cell is formed by the fusion of 2-polar nuclei. Thus, a typical angiospermic embryo sac or female gametophyte at maturity consists of 8-nuclei and 7-cells.

The egg cell combines with a male gamete to form zygote which becomes the embryo. The pollen tube makes its way through the synergids releasing the male gametes.

One male gamete fuses with female gamete (egg) called syngamy. The two polar nuclei which have fused to form secondary nucleus combine with second male gamete and form primary endosperm cell. This primary endosperm cell develops into endosperm which provides nutrition to the developing embryo. The antipodal cells degenerate.

Question 9.
Embryo
Answer:
Development of an Embryo: The first stage in the development of a plant zygote is a pre-determined mode of development (embryogeny).

It gives rise to an organised mass of cells called the embryo, that has the potentiality to form a complete plant. Most zygotes divide only after certain amount of endosperm is formed to assure proper nutrition is provided to the developing embryo.
In the majority of angiosperms, the zygote (fertilised egg) divides by an asymmetric mitotic division and generates two cells with two different fates

1. The smaller daughter cell with dense cytoplasm is situated towards the chalazal pole side. It is called terminal cell or apical cell or embryonal cell.
2. Another comparatively larger daughter cell situated towards the micropylar cell is called basal cell. This cell divides transversely and gives, rise to suspensor cells. The zygote gives rise to the proembryo anti subsequendy to the globular, heart-shaped and mature embryo.

Though the seeds differ greatly, the early stages of embryo development (embryogeny) are similar in monocots and dicots.

Question 10.
Micropropagation
Answer:
Micropropagation It is the production of large number of individual plants from a small piece of plant tissue cultured in a nutrient medium. It leads to formation of clones. It is a fast method of plant production.

Question 11.
Polyembryony
Answer:
Polyembryony
In general, each seed bears an embryo, but sometimes there are found more than one embryo in a single seed. The occurrence of more than one embryo in a seed is called polyembryony. It was first time observed in orange seeds by Antony van Leeuwenhoek in 1719.
On a broad basis, polyembryony is of two types

• Spontaneous It includes naturally occurring polyembryony.
• Induced This type of polyembryony is induced experimentally.

Question 12.
Incompatibility
Answer:
Incompatibility It is the inability of the pollen grains to germinate on the stigma of genetically similar plants or the failure of gametes to fuse or inability of the zygote to develop into a mature sporophyte.

Differentiate the following with at least three valid and meaningful points.

Question 1.
Pollination and Fertilisation.
Answer:
Differences between pollination and fertilisation are as follows

Pollination	Fertilisation
It refers to the transfer of pollen grains from an anther to stigma.	It refers to the fusion of male and female
It is a physical process.	It is cellular, genetic, biochemical process.
It can be achieved by various agents such as wind, insect, etc.	It is assisted by the plant itself.

 

Question 2.
Dichogamy and Herkogamy.
Answer:
Differences between dichogamy and herkogamy are as follows

Dichogamy	Herkogamy
When stamens and carpels of bisexual flowers mature at different times to prevent self-pollination, it is called dichogamy.	When some sort of barrier develops between stamens and pistil of same flowers and prevents self-pollination, it is called herkogamy.
It is of two types, i.e. protogyny and protoandry.	It is seen in Calotropis, etc.
It is seen in banana, coriander, etc.	It also prevents cross-pollination.
It prevents self-pollination.	Herkogamy

 

Question 3.
Protogyny and Protandry.
Answer:
Differences between protogyny and protandry are as follows

Protandry	Protogyny
In this, the anthers mature earlier so that its stigma is not ready to receive pollen from its anther.	In this, stigmas mature earlier so that they get pollinated before the anthers of the same flower mature and develop pollen grains.
e.g. in Salvia, sunflower, cotton, jasmine, etc.	e.g. in Plantago, Mirabilis jalapa, peepal, banyan, etc.

 

Question 4.
Self-pollination and Cross-pollination.
Answer:
Differences between self-pollination and cross-pollination are as follows

Self-pollination	Cross-pollination
Pollen grains are transferred from anther to stigma of the same flower (autogamy) or another flower borne on the same plant (geitonogamy).	Pollen grains are transferred from anther of one flower to stigma of another flower borne on a different plant of the same species (allogamy).
Both anthers and stigma mature at the same time.	The anthers and stigma of a flower mature at different times.
External agent is not required for self-pollination.	An external agent is essential for cross-pollination.
It is economical for the plant.	Cross-pollination is not economical as the plant has to produce a large number of pollen grains, nectar, ‘ scent and bright coloured corollas, etc.
It results in progenies which are purelines, e.g. homozygous.	It results in hybrids, e.g. heterozygous. They show variations in characters.

 

Question 5.
Embryo and Endosperm.
Answer:
Differences between embryo and endosperm are as follows

Embryo	Endosperm
It is formed by fertilised egg. (syngamy).	It is formed by fusion of secondary nucleus (triple fusion).
It is always diploid.	It is triploid. ‘
It gives rise to new plant.	It provides nutrition to the developing embryo.
Cotyledons, plumule and radicle are formed in embryo.	There is no formation of such structures.
Embryo is seen in seed.	It is only seen in endospermic seeds. Otherwise it degenerates with the formation of seed.

 

Question 6.
Gamete and Zygote.
Answer:
Differences between gamete and zygote are as follows

Gamete	Zygote
It is the cell that fuses with another cell in order to form zygote during fertilisation,	It is the fused product between an egg and a sperm.
Ploidy level of gametes is haploid.	Ploidy level of zygote is diploid.
Gamete is found in both male and female.	Zygote is only present in female.

 

Question 7.
Micropyle end and Chalazal end.
Answer:
Differences between micropyle end and chalazal end are as follows

Micropyle end	Chalazal end
In seed bearing plants, a small opening in the integuments of the ovule through which sperms are able to access the ovum.	In seed bearing plants, the location where the nucellus attaches to the integuments, opposite the micropyle.

 

Question 8.
Zoophily and Anemophily.
Answer:
Differences between zoophily and anemophily are as follows

Zoophily	Anemophily
Animal pollination is termed as zoophily. These animals can be bats, insects, birds, ants, etc.	Wind pollination is also termed as anemophily.
These flowers are large, colourful, fragrance and rich in nectar.	These flowers are small, colourless, inconspicuous and nectarless.
The pollen grains are produced in less number.	The pollar grains produced are more in number.

 

Question 9.
Double fertilisation and Triple fusion.
Answer:
Differences between double fertilisation and triple fusion are as follows

Double fertilisation	Triple fusion
It involves two processes, i.e. triple fusion and syngamy.	It is a process in angiosperms which occurs along with syngamy in the embryo.
It involves two sperm cells or male gametes.	It involves a single male gamete.
After double fertilisation zygote and an endosperm is formed.	It involves fusion of a male gamete with polar nuclei to form triploid endosperm.

 

Question 10.
Porogamy and Chalazogamy
Answer:
Differences between porogamy and chalazogamy are as follows

Porogamy	Chalazogamy
It is the condition when the pollen tube enters the ovule from the micropylar end during fertilisation.	It is the condition of entering of pollen tube from chalazal end during fertilisation.
e.g. in lily, etc.	e.g. in Casuarina, Jug Ians, etc.

 

Question 11.
Apospory and Apogamy.
Answer:
Differences between apospory follows and apogamy are as

Apospory	Apogamy
It is a type of reproduction in which gametophyte develops from sporophyte without meiosis and involvement of spores. The gametophyte usually develops from vegetative cells of sporophyte.	It is a type of reproduction in which sporophyte develops from gametophyte without fertilisation or fusion of gametes. The sporophyte usually develops from vegetative cells of gametophyte.

 

Question 12.
Monocot and Dicot embryo.
Answer:
Differences between monocot and dicot embryo are as follows

Monocot embryo	Dicot embryo
Basal cell forms a 6-10 celled suspensor.	Basal cell produces a single-celled suspensor.
Terminal cell produces embryo except the radicle.	It forms the whole of the embryo.
The first division of terminal cell is generally longitudinal.	It is transverse.
It has two cotyledons.	There is a single cotyledon.
Plumule is terminal and lies in between the two elongated cotyledons.	Plumule appears lateral due to excessive growth of the single cotyledon.

 

Question 13.
Nuclear and Cellular endosperm. (2018)
Answer:
Differences between nuclear and cellular endosperm are as follows

Nuclear endosperm	Cellular endosperm
Nuclear divisions are not followed by cell divisions.	Each division of nuclei is immediately followed by cell divisions.
The nuclear mass is then pushed to periphery and cell walls are laid. Mostly cell wall formation remains incomplete.	Complete cell walls are laid from the very beginning and a solid cellular mass is obtained,
A central vacuole is formed initially which ultimately disappears with a few exceptions.	No such vacuole is formed generally.
e.g. wheat, maize, rice, etc.	e.g. balsam, Datura, Petunia, etc.

 

Long Answer Type Questions

Question 1.
Distinguish between self and cross-pollination. Describe three conditions that favour cross-pollination.
Answer:
1. Autogamy (Self-Pollination)
It is the kind of pollination achieved within the same flower. The pollens from the anthers of a flower are transferred to the stigma of the same flower, e.g. wheat, rice, pea, etc., almost all the cleistogamous flowers are invariably autogamous as there is no chance of cross-pollination.

2. Geitonogamy
It is a kind of pollination where the pollen grains from the anther of a flower are transferred to the stigma of another flower borne on the same plant but at different branches. It usually occurs in plants which show monoecious condition, e.g. Cucurbita. It is functionally a type of cross-pollination (involving a pollinating agent), but genetically it is similar to autogamy (since pollen grains come from same plant).
Adaptations (Contrivances) for Self-Pollination The contrivances of self-pollination include homogamy, dichogamy and cleistogamy.

• Homogamy In this condition, both anther and stigma mature at the same time, e.g. Mirabilis.
• Dichogamy In this condition, anther and stigma mature at different times, e.g. sunflower.
• Cleistogamy The flowers which are always closed are known as cleistogamous, e.g. Oxalis.
  Self-pollination

Advantages of Self-Pollination

• Fertilisation and production of the progeny are always certain by this method.
• It maintains purity of race and superiority of the variety.
• Here there is less wastage of pollens.

Disadvantages of Self-Pollination

• It leads to loss of viability and vigour of the plant,in the long run.
• If lethal genes become homozygous, the effect may be disastrous.

3. Xenogamy (Cross-Pollination)
It involves the transfer of pollen grains from the anther of one plant to the stigma of another plant. This is the only type of pollination which brings genetically different types of pollen grains to the stigma during pollination, e.g. papaya, maize, etc.

Advantages of Cross-Pollination

• This always results in much healthier offsprings.
• The offsprings produced in this method are better adapted ones.
• As a result of the cross-pollination, hybrids are produced.
• More abundant and viable seeds are produced which store greater quantities of food material.
• The process eliminates defective characters and is helpful in production of new varieties.

Disadvantages of Cross-Pollination

• This is wasteful process, as large number of pollen grains get damaged in the course of pollination.
• The chance of fertilisation is limited here since it can be affected only if the pollen reaches the matured stigma.

Adaptations (Contrivances) for Cross-Pollination or Outbreeding Devices
Continued self-pollination leads to chances of inbreeding depression. Thus, flowering plants have developed many devices to discourage self-pollination and to encourage cross-pollination. These include
1. Dichogamy In some plant species, receptivity of stigma and pollen release is not synchronised, i.e. often the pollen is released before the stigma becomes receptive (protandry) or stigma becomes receptive before the release of pollen (protogyny). This condition is called dichogamy.

2. Heterostyly In some other species, the anther and stigma are placed at different positions, so that the pollen cannot come in contact with the stigma of same flower. This condition is called heterostyly.
Both the above mentioned methods will prevent autogamy.

3.Self-incompatibility or Self-sterility is the third device to prevent inbreeding. It is a genetic phenomenon of preventing the pollen from fertilising ovules by the same flower by inhibiting pollen germination or pollen tube growth in the pistil. Self-incompatibility may be due to genotype of sporophyte known as sporophytic incompatibility, whereas if it is due to genotype of pollen, it is known as gametophytic incompatibility.

4.Dicliny or Unisexuality effectively prevents self-pollination. It is the presence of unisexual flowers in plants that prevents autogamy but not geitonogamy, e.g. castor, maize, etc.

5.Herkogamy is seen in orchids where male or female sex organs themselves prove as a barrier to prevent self-pollination by some structural abnormalities.

6.Dioecy Both autogamy and geitonogamy is prevented in several species like papaya, where male and female flowers are present on different plants, i.e. each plant is either male or female (dioecy).

Question 2.
What is cross-pollination? Give an account of the contrivances of cross-pollination.
Answer:
Xenogamy (Cross-Pollination)
It involves the transfer of pollen grains from the anther of one plant to the stigma of another plant. This is the only type of pollination which brings genetically different types of pollen grains to the stigma during pollination, e.g. papaya, maize, etc.

Advantages of Cross-Pollination

• This always results in much healthier offsprings.
• The offsprings produced in this method are better adapted ones.
• As a result of the cross-pollination, hybrids are produced.
• More abundant and viable seeds are produced which store greater quantities of food material.
• The process eliminates defective characters and is helpful in production of new varieties.

Disadvantages of Cross-Pollination

• This is wasteful process, as large number of pollen grains get damaged in the course of pollination.
• The chance of fertilisation is limited here since it can be affected only if the pollen reaches the matured stigma.

Adaptations (Contrivances) for Cross-Pollination or Outbreeding Devices
Continued self-pollination leads to chances of inbreeding depression. Thus, flowering plants have developed many devices to discourage self-pollination and to encourage cross-pollination. These include
1. Dichogamy In some plant species, receptivity of stigma and pollen release is not synchronised, i.e. often the pollen is released before the stigma becomes receptive (protandry) or stigma becomes receptive before the release of pollen (protogyny). This condition is called dichogamy.

2. Heterostyly In some other species, the anther and stigma are placed at different positions, so that the pollen cannot come in contact with the stigma of same flower. This condition is called heterostyly.
Both the above mentioned methods will prevent autogamy.

3.Self-incompatibility or Self-sterility is the third device to prevent inbreeding. It is a genetic phenomenon of preventing the pollen from fertilising ovules by the same flower by inhibiting pollen germination or pollen tube growth in the pistil. Self-incompatibility may be due to genotype of sporophyte known as sporophytic incompatibility, whereas if it is due to genotype of pollen, it is known as gametophytic incompatibility.

4.Dicliny or Unisexuality effectively prevents self-pollination. It is the presence of unisexual flowers in plants that prevents autogamy but not geitonogamy, e.g. castor, maize, etc.

5.Herkogamy is seen in orchids where male or female sex organs themselves prove as a barrier to prevent self-pollination by some structural abnormalities.

6.Dioecy Both autogamy and geitonogamy is prevented in several species like papaya, where male and female flowers are present on different plants, i.e. each plant is either male or female (dioecy).

Question 3.
Describe how different agents help in cross-pollination.
Answer:
Agents of Cross-Pollination
The agents responsible for pollination in angiospermshave been grouped into two main categories

To compensate for the chances of contact of pollen grains with stigma and associated loss of pollen grains, the plants have adopted various ways.
Some of them are
Adaptations for Wind Pollination
Wind pollination is also termed as anemophily and is the most common amongst abiotic pollinations.
The adaptations of wind pollinated flowers are

• Flowers are small, colourless, inconspicuous and nectarless.
• Wind pollinated flowers often have a single ovule in each ovary and numerous flowers packed into an inflorescence like in tassels of corn cob (i.e. stigma and style).
• The anthers are well-exposed for the easy dispersal of pollen grains.
• Pollen grains are small, light, dry, dusty, non-sticlcy and sometimes even winged.
• The stigma are large, hairy and feathery or branched to catch the air-borne pollen grains.
• Common examples of wind pollinated flowers are grasses, sugarcane, bamboo, coconut, etc.
  

Adaptations for Water Pollination
Water pollination is also termed as hydrophily. It is quite rare in flowering plants and is limited to about 30 genera, mostly monocotyledons.
The adaptations of water pollinated flowers are

• It is very common in lower plant groups such as algae, bryophytes and pteridophytes. Flowers are small, colourless, inconspicuous, odourless and nectarless.
• The stigmas are long and sticky, e.g. Vallisneria, Hydrilla and Zostera (sea-grasses).
• In most of the water pollinated species, pollen grains are protected from getting wet by mucilaginous covering.
• Not all aquatic plants use water for pollination. In a majority of aquatic plants, the flowers emerge above the level of water and are pollinated by insects or wind as in land plants, e.g. water hyacinth and water lily.
• In Vallisneria, the female flowers reach the surface of water by the long stalk and male flowers or pollen grains are released on to the surface of water. They are then carried passively by water currents.
• In plants like sea grasses, female flowers remain submerged in water and the pollen grains are released inside the water. In such species, pollen grains are long, ribbon-like and are carried passively inside the water to reach stigma and achieve pollination.
• Pollination taking place under water is known as hypohydrogamous whereas pollination taking place on surface of water is called epihydrogamous.
  

Adaptations for Insect Pollination
Insect pollination is also termed as entomophily.
The adaptations of insect pollinated flowers are

• Insect pollinated flowers are large, colourful, fragrant and rich in nectar.
• A number of flowers are clustered into an inflorescence to make them conspicuous, when the .flowers are small.
• Flowers have nectar glands and are highly fragrant to attract insects.
• The surface of pollen grains is sticky due to exine layer and stigma is sticky due to mucilaginous layer.
• To sustain animal visits, flowers have to provide rewards. Nectar and pollen grains are floral rewards for the insect pollinators.
• In some species, floral rewards are to provide safe place for laying eggs, e.g. Amorphophalius (the tallest flower abput 6 feet in height).
• In plant Yucca, moth and the plant cannot complete their life cycles without each other. The moth deposits its eggs in the locule of the ovary and the flower, in turn, gets pollinated by the moth. The larvae of the moth come out of the eggs as the seeds start developing.
• Many insects may consume pollen or the nectar without bringing about pollination. These floral visitors are referred to as pollen/nectar robbers.

Some special mechanisms in case of insect pollination are as follows

1. In case of Bignonia where the stigma gets exposed by opening the flap closed by visit of insect.
2. In hypanthodium inflorescence, the insects enter through ostiole which is a pore which opens the inflorescence to outside.
   In this inflorescence, three types of flowers occur. The insect when visits, it passes through anthers of male flowers and then reaches female flowers which are present in middle part of inflorescence. This results in pollination.
3. Another adaptation occurs in Salvia where there is the presence of a bilabiate corolla with two epipetalous stamens.
   
   Insect pollination in Salvia-, (a) A structure of flower, (b) Diagrammatic representation of changes taking place in the position of anther lobes during the entry of insect in the flower, (c) Entry of insect in the flower [note the dusting of pollen grains on the back of the insect], (d) Insect entering another flower and the pollens on its back being collected by stigma

Question 4.
Discuss the important outbreeding devices for cross-pollination.
Answer:
Adaptations (Contrivances) for Cross-Pollination or Outbreeding Devices
Continued self-pollination leads to chances of inbreeding depression. Thus, flowering plants have developed many devices to discourage self-pollination and to encourage cross-pollination. These include
1. Dichogamy In some plant species, receptivity of stigma and pollen release is not synchronised, i.e. often the pollen is released before the stigma becomes receptive (protandry) or stigma becomes receptive before the release of pollen (protogyny). This condition is called dichogamy.

2. Heterostyly In some other species, the anther and stigma are placed at different positions, so that the pollen cannot come in contact with the stigma of same flower. This condition is called heterostyly.
Both the above mentioned methods will prevent autogamy.

3.Self-incompatibility or Self-sterility is the third device to prevent inbreeding. It is a genetic phenomenon of preventing the pollen from fertilising ovules by the same flower by inhibiting pollen germination or pollen tube growth in the pistil. Self-incompatibility may be due to genotype of sporophyte known as sporophytic incompatibility, whereas if it is due to genotype of pollen, it is known as gametophytic incompatibility.

4.Dicliny or Unisexuality effectively prevents self-pollination. It is the presence of unisexual flowers in plants that prevents autogamy but not geitonogamy, e.g. castor, maize, etc.

5.Herkogamy is seen in orchids where male or female sex organs themselves prove as a barrier to prevent self-pollination by some structural abnormalities.

6.Dioecy Both autogamy and geitonogamy is prevented in several species like papaya, where male and female flowers are present on different plants, i.e. each plant is either male or female (dioecy).

Question 5.
Describe how double fertilisation and triple fusion occur in the angiosperms.
Answer:
Double Fertilisation
Fertilisation was discovered by Strasburger. But the process of double fertilisation was demonstrated for the first time by Nawaschin in 1898 in Lilium and Fritillaria. The most important and unique characteristic feature of angiosperms is the participation of both male gametes in the act of fertilisation.

The pollen tube releases the two male gametes into the cytoplasm of one of the synergids, then the penetrated synergid starts degenerating. One male gamete fuses With the egg cell to form a diploid(2«) zygote. This process is called syngamy or generative fertilisation.

1. The diploid zygote finally develops into’the embryo.
2. The second male gamete fuses with the two polar nuclei or secondary nucleus in the central cell to form the triploid Primary Endosperm Nucleus (PEN).
3. The process is called triple fusion as three haploid nuclei are involved in the fusion. After triple fusion, the central cell becomes the Primary Endosperm Cell (PEC) which gives rise to the endosperm, while the zygote develops into the embryo. As both the fusions, syngamy and triple fusion, occur in an embryo sac, the phenomenon is termed as double fertilisation.

Question 6.
With diagrams, describe the development of male and female gametophyte in angiosperms.
Answer:
Development of a Male Gametophyte
Microspore is the first cell of male gametophyte. It involves formation of microsporangium and development of male gametophyte at pre-pollination and post-pollination events. The structures are stages which lead to development of male gametophyte are as follows
Stamen:
It is the male reproductive unit of angiosperm.
It consists of two parts

• The long and slender stalk called the filament.
• The terminal generally bilobed structure called the anther.

The anther and filament are connected by a connective.

Structure of an Anther
A typical angiosperm anther is bilobed structure with each lobe having two theca (dithecous) and separated by a longitudinal groove running lengthwise.
In a cross-section, the anther is a four-sided (tetragonal) structure consisting of four microsporangia located at the corners, two in each lobe. Later, the microsporangia develop and become pollen sacs, which are packed with the pollen grains.

Formation of Microsporangium (Pollen Sacs)
A typical microsporangium is surrounded by four wall layers, i.e. the epidermis, endothecium, middle layer and the tapetum. The outer three wall layers are protective in function and help in dehiscence of anther to release pollen grains. Tapetum (innermost layer) nourishes the developing microspores or pollen grains and the cells of tapetum possess dense cytoplasm and generally have more than one nucleus. When the anther is young, a group of compactly arranged homogenous cells called the sporogenous tissue occupies the centre of each microsporangium.

A young anther possesses a homogenous mass of hypodermal cells bounded by epidermis. After some time, this homogenous mass appears like a tetra-angular mass. Inner to this epidermis, some cells at each angle contain a prominent nucleus and abundant protoplasm, they are . called archesporial cells.

Development of microsporangium (a-e) successive stages of the development of microsporangium, (f) A mature pollen sac in a

Development of a Female Gametophyte:
The process of female gametophyte formation is called megagametogenesis. The process involves pistil which is the female reproductive part.
The stages like development of ovule, megasporogenesis followed by organisation of female gametophyte complete the process.
These structures and stages are discussed as follows

Pistil:
The gynoecium represents the female reproductive part of the flower. It may consist of one pistil or carpel (monocarpellary), two carpels (bicarpellary), three carpels (tricarpellary) or many carpels (multicarpellary). Pistil may be syncarpous (i.e. more than one pistils are fused together) as in Papaver, Solanum, etc., or may be apocarpous (i.e. carpels remain free) as in Michelia, rose, etc.

(a) Multicarpellary, syncarpous pistil of Papaver and (b) Multicarpellary, apocarpous gynoecium of Michelia

A typical pistil consists of a hollow basal swollen ovary, an elongated style and a terminal stigma (serves as a landing platform for pollen grains). Inside the ovary is the ovarian cavity (locule) in which placenta is located. Megasporangia (ovules) arise from placenta.

Gynoecium: (A) External view, (B) Transverse section of ovary

The mode of arrangement of ovule along the placenta in the cavity of the ovary is known as placentation (axile, parietal, free-central, etc).

Megasporangium (Ovule):
The ovule is an integumented megasporangium within which the meiosis and megaspore formation take place. It is attached to the placenta by means of a stalk called funicle. It develops into a seed after fertilisation. The junction between an ovule and funicle is called hilum, which later becomes a scar on the seed. Each ovule has one or two protective envelopes called integuments, which encircle the ovule except at a tip where a small opening called micropyle is located.

Ovule : Structure tAnatropous ovule

The basal part of an ovule just opposite to micropyle is called chalaza. Enclosed within the integuments is a mass of cells called nucellus. Cells of the nucellus are rich in reserve food materials. An ovule generally has a single embryo sac or female gametophyte developed from a megaspore through reductional division and located within the nucellus.

Structure of Ovule:
Depending upon the shape and orientation, the ovules of angiosperms are classified into following types

1. Orthotropous or atropous where the micropyle, chalaza and funicle are in a straight line, e.g. Piper.
2. Anatropous where the body of the ovule is completely inverted, e.g. 82% of angiosperms.
3. Hemianatropous where ovule turns at the angle of 90° upon the funicle, e.g. Ranunculus.
   
   (a-f) Various types of ovules : (a) Orthotropous, (b) Anatropous, (c) Hemianatropous, (d) Campylotropous, (e) Amphitropous, (f) Circinotropous
4. Campylotropous where ovule is circled more or less at right angle to funicle, e.g. legumes.
5. Amphitropous where the embryo sac becomes curved like horse-shoe, e.g. Lemna.
6. Circinotropous where funicle completely surrounds the body of the ovule, e.g. Opuntia.

Development of the Ovule:
The development of ovule starts with the formation of a primordium on the placenta first periclinal divisions occur which are followed by anticlinal divisions which cause enlargement of the protruberance. An archesporial cell gets differentiated by acquiring size and dense cell contents. This is followed by initiation of formation of outer and inner integuments.

(A-D) Successive stages in the development , of ovule

These integuments appear as a complete ring and cover the whole nucellus except at the micropylar opening. These integuments enclose the central part of ovule which is a parenchymatous mass of cells. This region gets differentiated to form mature nucellus enclosing a female gametophyte. At the end, the ovule consists of integuments and nucellus which possess embryo sac.

Organisation of Female Gametophyte (Embryo Sac):
In general, the development of embryo sac is monosporic, e.g. in Polygonum. In this type of development, only one megaspore situated towards chalazal end remains functional, while the remaining three megaspores gradually degenerate and finally disappear. Following are the different stages in development of female gametophyte

1. The functional haploid megaspore is the first cell of female gametophyte of angiosperm.
2. It enlarges in size to form the female gametophyte, also called embryo sac.
3. Its nucleus undergoes mitotic division to form 2-nuclei that move to opposite poles forming 2-nucIeate embryo sac.
4. The 2-nucleate embryo sac undergoes two more sequential mitotic divisions giving rise to the 4-nucleate stage and later 8-nucleate stage of embryo sac. This stage comprises of a micropylar end and a chalazal end with four nuclei at each end.
5. Six of the eight nuclei are surrounded by cell walls and get organised into cells. Three cells present towards the micropylar end grouped together, constitute the egg apparatus, i.e. two synergids and one egg cell.
6. Three cells of the chalazal end are called the antipodals. The large central cell is formed by the fusion of 2-polar nuclei. Thus, a typical angiospermic embryo sac or female gametophyte at maturity consists of 8-nuclei and 7-cells.

The egg cell combines with a male gamete to form zygote which becomes the embryo. The pollen tube makes its way through the synergids releasing the male gametes.

One male gamete fuses with female gamete (egg) called syngamy. The two polar nuclei which have fused to form secondary nucleus combine with second male gamete and form primary endosperm cell. This primary endosperm cell develops into endosperm which provides nutrition to the developing embryo. The antipodal cells degenerate.