CHSE Odisha Class 12 Biology Solutions Chapter 9 Health and Diseases

Odisha State Board CHSE Odisha Class 12 Biology Solutions Chapter 9 Health and Diseases Textbook Questions and Answers.

CHSE Odisha 12th Class Biology Chapter 9 Question Answer Health and Diseases

Health and Diseases Class 12 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Multiple choice questions

Question 1.
Which one of the following diseases are communicable ?
(a) Deficiency diseases
(b) Allergies
(c) Degenerative diseases
(d) Infectious diseases
Answer:
(d) Infectious diseases

Question 2.
The nature of the spread of communicable diseases is termed as
(a) parasitology
(b) immunology
(c) epidemiology
(d) None of these
Answer:
(c) epidemiology

Question 3.
Which one of the following is a sexually transmitted disease ?
(a) Q-fever
(b) Leprosy
(c) Whooping cough
(d) Gonorrhoea
Answer:
(d) Gonorrhoea

Question 4.
Gonorrhoea is a
(a) bacterial disease
(b) Veneral disease
(c) STD
(d) All of these
Answer:
(c) STD

Question 5.
Anthrax is caused by
(a) Vibrio
(b) Bacillus
(c) Salmonella
(d) virus
Answer:
(b) Bacillus

Question 6.
Some common diseases caused by bacteria are
(a) measles, mumps and malaria
(b) tetanus, typhoid and tuberculosis
(c) syphilis, smallpox and sleeping sickness
(d) pneumonia, poliomyelitis and psittacosis
Answer:
(b) tetanus, typhoid and mberculosis

Question 7.
Which one of the following disease is spread through wounds ?
(a) Tetanus
(b) Cholera
(c) Plague
(d) Tuberculosis
Answer:
(a) Tetanus

Question 8.
Which of the following is a bacterial disease ?
(a) Measles
(b) Smallpox
(c) Rabies
(d)Tuberculosis
Answer:
(d)Tuberculosis

Question 9.
Causative agent of TB is
(a) Salmonella
(b) Streptococcus
(c) Mycobacterium
(d) Pneumococcus
Ans.
(c) Mycobacterium

Question 10.
BCG vaccine is a preventive measure against
(a) Tuberculosis
(b) Typhoid
(c) AIDS
(d) Cholera
Ans.
(a) Tuberculosis

Question 11.
Which one is not a bacterial disease ?
(a) Tuberculosis
(b) Typhoid
(c) AIDS
(d) Cholera
Ans.
(c) AIDS

Question 12.
Mantoux test is for
(a) scarlet fever
(b) diptheria
(c) rheumatoid fever
(d) tuberculosis
Ans.
(d) tuberculosis

Question 13.
Chickenpox is caused by
(a) Varicella virus
(b) adenovirus
(c) SV-40 virus
(d) bacteriophage-T₂
Ans.
(a) Varicella virus

Question 14.
Smallpox is due to
(a) virus
(b) bacterium
(c) protozoan
(d) helminth
Ans.
(a) virus

Question 15.
The disease caused by virus is
(a) pneumonia
(b) tuberculosis
(c) smallpox
(d) typhoid
Ans.
(c) smallpox

Question 16.
Polio is caused by
(a) virus with double-stranded DNA
(b) virus with double-stranded RNA
(c) virus with single-stranded DNA
(d) virus with single-stranded RNA
Ans.
(d) virus with single-stranded RNA

Question 17.
Mumps is a
(a) protozoan disease
(b) viral disease
(c) fungal disease
(d) bacterial disease
Ans.
(b) viral disease

Question 18.
Which one is a viral disease ?
(a) Measles
(b) Rickets
(c) Syphilis
(d) Congenital night blindness
Answer:
(a) Measles

Question 19.
Amoebiasis is caused by
(a) Plasmodium vivax
(b) Entamoeba gingivalis
(c) Trypanosoma gambiense
(d) Entamoeba histolytica
Answer:
(d) Entamoeba histolytica

Question 20.
Entamoeba histolytica infection occurs through
(a) mosquito bite
(b) bird droppings
(c) sweat
(d) contaminated food and water
Answer:
(d) contaminated food and water

Question 21.
The infective stage of Entamoeba histolytica is
(a) binucleate form
(b) tetranucleate form
(c) minute form
(d) sporozoite stage
Answer:
(b) tetranucleate form

Question 22.
Malaria is transmitted by
(a) male Anopheles
(b) female Anopheles
(c) female Culex
(d) female Aedes
Answer:
(b) female Anopheles

Question 23.
Select the incorrect pair
(a) Pedicuius-Typhoid
(b) Xenopsylla-Plague
(c) Culex-Malaria
(d) Aedes-Yellow fever
Answer:
(a) Pedicuius-Typhoid

Question 24.
Filaria is transmitted by
(a) tse-tse fly
(b) sand fly
(c) Anopheles
(d) Culex
Answer:
(b) sand fly

Question 25.
Culex causes the disease
(a) malaria
(b) filariasis
(c) yellow fever
(d) sleeping sickness
Answer:
(b) filariasis

Question 26.
The disease elephantiasis is caused by
(a) Culex mosquito
(b) Anopheles mosquito
(c) housefly
(d) tse-tse fly
Answer:
(a) Culex mosquito

Question 27.
Microfilariae are found in the peripheral blood of man during
(a) day time
(b) day and night time
(c) night time
(d) None of the above
Answer:
(c) night time

Question 28.
Infection of Ascaris occurs due to
(a) tse-tse fly
(b) mosquito bite
(c) imperfectly cooked pork
(d) contaminated food and water
Answer:
(d) contaminated food and water

Question 29.
A disease caused by nematode parasite
(a) filariasis
(b) leprosy
(c) amoebiasis
(d) poliomyelitis
Answer:
(a) filariasis

Question 30.
AIDS is caused by
(a) HTLV-III
(b) herpes virus
(c) rotavirus
(d) orthomyxovirus
Answer:
(a) HTLV-III

Question 31.
Cerebral malaria is caused by Plasmodium
(a) vivax
(b) ovale
(c) falciparum
(d) All of these
Answer:
(c) falciparum

Question 32.
Which of the glands is often referred in relation with AIDS?
(a) Thyroid
(b) Adrenal
(c) Thymus
(d) Pancreas
Ans.
(c) Thymus

Question 33.
AIDS is caused by
(a) virus
(b) fungus
(c) helminth
(d) bacterium
Ans.
(a) virus

Question 34.
AIDS is due to
(a) reduction in number of helper T-cells
(b) lack of interferon
(c) reduction is number of killer T-cells
(d) auto-immunity
Answer:
(a) reduction in number of helper T-cells

Question 35.
AIDS virus has
(a) double-stranded DNA
(b) single-stranded DNA
(c) single-stranded RNA
(d) double-stranded RNA
Ans.
(c) single-stranded RNA

Question 36.
AIDS spreads through
(a) immoral way of life
(b) infected needles and syringes
(c) homosexuality
(d) All of the above
Ans.
(d) All of the above

Question 37.
Cancer is
(a) non-malignant tumour
(b) controlled division of cells
(c) unrestrained division of cells
(d) microbial infection
Ans.
(c) unrestrained division of cells

Question 38.
Cancer cells are damaged by radiations while others are not
(a) being different in nature
(b) being starved
(c) undergoing rapid division
(d) None of the above
Answer:
(c) undergoing rapid division

Question 39.
Sarcoma is the cancer of
(a) epithelial tissues
(b) connective tissues
(c) blood
(d) endodermal tissues
Answer:
(b) connective tissues

Question 40.
Blood cancer is called
(a) leukemia
(b) haemophilia
(c) thrombosis
(d) haemolysis
Answer:
(a) leukemia

Question 41.
The cells affected by leukemia are
(a) plasma cells
(b) erythrocytes
(c) thrombocytes
(d) leucocytes
Answer:
(a) plasma cells

Question 42.
Genes involved in cancer are
(a) tumour genes
(b) oncogenes
(c) cancer genes
(d) regulator genes
Answer:
(b) oncogenes

Question 43.
Oncology is the study of
(a) living cells
(b) cancer cells
(c) dead cells
(d) dividing cells
Answer:
(b) cancer cells

Question 44.
The most common cancer in women is
(a) breast cancer
(b) skin cancer
(c) cervix cancer
(d) leukemia
Answer:
(a) breast cancer

Question 45.
Breast cancer is an examle of
(a) adenoma
(b) lymphoma
(c) carcinoma
(d) sarcoma
Answer:
(c) carcinoma

Question 46.
Cancer treatment includes
(a) surgery
(b) radiotherapy
(c) treatment with anticancer drugs
(d) All of the above
Answer:
(d) All of the above

Question 47.
The most common type of cancer in man is
(a) skin cancer
(b) lung cancer
(c) cancer of prostate
(d) cancer of bladder
Answer:
(b) lung cancer

Question 48.
Which one of the following is a cancer causing agent ?
(a) Tobacco
(b) Radiation
(c) Smoking
(d) All of these
Answer:
(d) All of these

Question 49.
Which one of the following is an oncogenic virus ?
(a) Herpes simplex-II
(b) Papilloma
(c) Epstein-Barr
(d) All of these
Answer:
(c) Epstein-Barr

Question 50.
The spread of cancerous cells to distant sites is termed
(a) metamorphosis
(b) metagenesis
(c) metastasis
(d) metachrosis
Answer:
(c) metastasis

Question 51.
Adenoma refers to the cancer of
(a) glands
(b) lymph nodes
(c) blood
(d) muscles
Answer:
(a) glands

Question 52.
Which one of the following is an anticancer drug?
(a) Aspirin
(b) Flagyl
(c) Streptomycin
(d) Vincristine
Answer:
(d) Vincristine

Question 53.
Which of the following scientists got Noble prize in 1989 for the studies on the genetic basis of cancer ?
(a) Philip Sharp and Richard Roberts
(b) David Baltimore and Howard Temin
(c) Michael Bishop and Harold Varmus
(d) Stanley B Prusiner
Answer:
(c) Michael Bishop and Harold Varmus

Question 54.
HIV attacks which one of the following ?
(a) B-cells
(b) T- cells
(c) Antigen preventing cell
(d) T-helper cells
Answer:
(d) T-helper cells

Question 55.
Which one of the following is not a component of innate immunity ?
(a) Antibodies
(b) Interferons
(c) Complement proteins
(d) Phagocytes
Answer:
(a) Antibodies

Question 56.
Which of the following is involved in defense mechanism of the body ?
(a) Lymphocytes
(b) Neutrophils
(c) Macrophages
(d) All of these
Answer:
(d) All of these

Question 57.
During allergic reactions, which of the following is secreted ?
(a) Allergens
(b) Histamines
(c) Immunoglobulins
(d) Pyrogens
Answer:
(b) Histamines

Question 58.
Immunoglobulins are
(a) antigen
(b) antibodies
(c) antiseptics
(d) antibiotics
Answer:
(b) antibodies

Question 59.
B-lymphocytes are produced by
(a) liver
(b) thymus
(c) spleen
(d) bone marrow
Answer:
(d) bone marrow

Question 60.
Cell-mediated immunity is due to
(a) B-cells
(b) T-cells
(c) T-helper cells
(d) All of these
Answer:
(b) T-cells

Question 61.
The cells which release the antibodies are
(a) helper T- cells
(b) B-cells
(c) plasma cells
(d) T-cells
Answer:
(b) B-cells

Question 62.
Antiviral substances are
(a) antibodies
(b) antibiotics
(c) interferons
(d) vaccines
Answer:
(c) interferons

Question 63.
The major phagocytic cells are
(a) lymphocytes
(b) mast cells
(c) macrophages
(d) plasma cells
Answer:
(c) macrophages

Question 64.
Which immunoglobulin is the largest in size ?
(a) IgA
(b) IgD
(c) IgE
(d) IgM
Answer:
(d) IgM

Question 65.
Vaccine for rabies was first produced by
(a) Louis Pasteur
(b) Edward Jenner
(c) Paul Berg
(d) None of these
Answer:
(a) Louis Pasteur

Question 66.
Vaccination means introduction in our body of
(a) weakened germs
(b) WBCs from other animals
(c) antibodies
(d) All of the above
Answer:
(a) weakened germs

Question 67.
The biochemical basis of vaccination was given by
(a) Louis Pasteur
(b) Salk
(c) Kohler
(d) Edward Jenner
Answer:
(d) Edward Jenner

Question 68.
Against which foreign organism (antigen) antibiotic is effective?
(a) Virus
(b) Bacteria
(c) Fungal infection
(d) Protozoan
Answer:
(b) Bacteria

Fill in the blanks

Question 1.
The immunity, present right from birth is known as ………….. immunity.
Answer:
innate

Question 2.
The immunity generated on exposure to foreign antigens is known as ………… immunity.
Answer:
acquired

Question 3.
Anti Tetanus Serum (ATS) administration generates ……….. immunity in the body.
Answer:
artificial passive

Question 4.
Toxoid is an example of ………. immunity.
Answer:
adaptive

Question 5.
A part of an antigen that evokes an immune response is called antigen …………
Answer:
determinant (epitope)

Question 6.
Antibodies segregate with ………. class of serum proteins.
Answer:
immunogens

Question 7.
The stem of the ‘Y’-shaped immunoglobulin molecule carries out …………. functions.
Answer:
effector

Question 8.
Among all immunoglobulins ………… can cross the placental barrier.
Answer:
IgM

Question 9.
During primary immune response, ………… immunoglobulin is predominant.
Answer:
IgG

Question 10.
Immunoglobulin ……………. is present in the mother’s milk, tear and saliva.
Answer:
IgA

Question 11.
Formation of antibodies against self antigens leads to an ………… disorder.
Answer:
autoimmune

Question 12.
……………… released by mast cells causes inflammatory response.
Answer:
Histamine

Question 13.
Humans get AIDS virus from
Answer:
HIV contaminated needle

Question 14.
The tests conducted for determining AIDS and typhoid are test and test respectively.
Answer:
ELISA, Widal

Answer the following in one or a few sentences

Question 1.
What is passive acquired immunity ? Explain.
Answer:
It is the immunity which is acquired by readymade antibodies or sensitised WBC directly injected to a person. It provides immediate relief and is not long lasting. It is classified as
• Natural passive acquired immunity
• Artificial passive acquired immunity

Question 2.
What is an antigenic determinant (epitope)?
Answer:
Epitope is the component or an active site of an antigen which binds to the complementary past of an antibody called paratope. It is also known as antigenic determinant.

Question 3.
Explain humoral immunity.
Answer:
The immunity which is mediated by antibodies present in blood and lymph is known as humoral immunity or immune response.

Question 4.
Explain about the antigen binding sites of an antibody.
Answer:
‘Y’-shaped antibody molecule possesses antigen-binding sites and are known as Fragment antigen binding (Fab). This site has the ability to recognise a complementary antigen and bind to it.

Question 5.
Mention about the effector functions of an antibody.
Answer:
Antibodies have several mechanisms by which they act in body. To combat pathogens which are replicated outside cells, antibodies binds to pathogens to link them together.
It causes them to agglutinate. So, by coating the pathogen, antibodies stimulate effector functions against pathogen.

Question 6.
How do antigens interact with their antibodies?
Answer:
Antigen-Antibody Interaction:
Antigens or immunogens are whole organisms or foreign particles that can evoke immune responses and can bind to antibodies in a specific manner. An antibody interacts with the small specific part of an antigen, called epitope or antigenic determinant. Epitope is the immunologically specific component or active site of an antigen, which hinds to the complementary part of an antibody called paratope.

Question 7.
What is a toxoid ? Name the bacterial diseases against which toxoids are used as vaccines.
Answer:
Some pathogenic bacteria producess exotoxins which are isolated and chemically modified to reduce their toxicity. Such exotoxins are non-toxic immunogenic deterivatives also called as toxoids. Diphtheria and tetanus vaccines are produced from toxoids and treat bacterial diseases.

Question 8.
What is an oral polio vaccine?
Answer:
Polio is an infectious disease caused by a virus. Oral Polio Vaccine or OPV are the predominant vaccine used to eradicate polio. Oral polio vaccine results in vaccine associated paralytic polio.

Question 9.
What is immunosuppression?
Answer:
The reduction of activation of immune system is called immuno suppression. It can either be deliberate or as an adverse effect of any therapeutic agent. The major causes of immunosuppression are diabetes, chronic alcoholism, renal failure, autoimmune disorders or CNS infection.

Question 10.
Explain autoimmune haemolytic anaemia.
Answer:
The condition in which antibodies of a person target their own blood cells and cause them to burst, leading to an insufficient oxygen carrying blood cells in the circulatory system, is called Autoimmune Haemolytic Anaemia (AIHA).

Question 11.
What is an immune deficiency?
Answer:
The state in which immune system’s ability to fight diseases is negligible or completely absent is called immunodeficiency. It usually occurs as a result of extrinsic factors which includes HIV infection, extremes of age or environmental factors.

Question 12.
Explain reticular dysgenesis.
Answer:
Reticular Dysgenesis (RD ) is a rare inherited autosomal recessive disease that results in immune deficiency. A weakened immune system leave patients susceptible to different kinds of infections.

Short Answer Type Questions

Question 1.
What is the causative organism of filariasis and write a note on its prevention and control.
Answer:
The causative organism of filariasis is Wuchereria bancrofii and Wuchereria malayi and Culex mosquito is the vector. Anti-mosquito measures are taken to eliminate the breeding places for the vectors which causes filariasis and also helps to control the spread.

Question 2.
Write the names of five drugs to control malaria.
Answer:
The drugs which helps to control malaria.
(i) Chloroquine
(ii) Doxycycline
(iii) Resochins
(iv) Paludrine
(v) Daraprim

Question 3.
What are the different species of malarial parasite?
Answer:
Malaria is caused by potozoan parasite Plasmodium. The four different species which cause malaria in humans

• P. falciparum
• P. ovale
• P. malarial
• P. vivax

Question 4.
What are the causes of non-communicable diseases?
Answer:
The major causes for the occurrence of non-communicable diseases are

• Air-borne germs These are spread through air to a healthy individuals. Common diseases which spread through air-borne germs are measles, tuberculosis and chicken pox.
• Direct/ indirect contact With a person suffering from communicable diseases can cause the spread.
• Food borne/water borne The disease can also be caused by sharing food or water with infected person.

Question 5.
What are the measures taken to control malaria?
Answer:
Control Malaria:
In 1979, WHO expert committee summarised few antimalarial measures. These are

• Use of mosquito repellents, bed-nets and cleaning of houses.
• Use of aerosols near domestic area.
• Destroy mosquito larvae by larvicides by using larvivorous fishes like Gambusia.
• Manage water fills and digs to prevent the area from the development of larvae.
• Chemoprophylaxis or little dose of quinine to be administered in malaria prone area.
• Chemotherapy in which medicines like quinine, paluidine, camoquin, resochin, mepacrine, lavagnin, daraprin, etc., are given to people to prevent them from malarial infection.

Question 6.
Write a short note on tumour and their types.
Answer:
It involves the following common methods

• Surgery In this primary approach, tumours are removed by surgery to check further spread of cancer cells.
• Radiotherapy In this technique, tumour cells are irradiated by lethal doses of radiation by protecting the surrounding normal cells.
• Chemotherapy In this several chemotherapeutic drugs are used to kill cancer cells. But their side effects like hair loss, anaemia are also reported.
• Immunotherapy In this process of treatment, several biological modifiers like a-interferons are used to activate the immune system and help in destroying the tumour.

Question 7.
What is ascariasis and how it is controlled?
Answer:
Ascariasis:
It is caused by an intestinal endoparasite of human, i.e. Ascaris lumbricoides commonly known as roundworm. It is the most common nematode parasite that occurs worldwide and mostly found in tropical and subtropical areas where hygiene and sanitation are poor. The adult female is about 12 inches in length while male adults are smaller.

Infection is more common in rural areas of South-Eastern part in India. Children get more affected than adults by this disease due to poor sanitation habits.

Control:
Few preventive measures are given below

• Maintain personal hygiene.
• Consume thoroughly washed and properly cooked vegetables and fruits.
• Drink packaged or boiled water.
• Disposal of fecal matter away from habitation crops and water sources.
• Do not let children to play in soil.

Question 8.
Write a short note on amoebiasis.
Answer:
It is caused by Entamoeba histolytica which is found inside or outside the intestine. The symptoms of intestinal amoebiasis are amoebic dysentry, non-dysentric colitis, amoeboma and amoebic appendicitis leading to complications like intestinal perforation, peritonitis and haemorrhage. The extra-intestinal amoebiasis can also occur in liver, lungs, brain, spleen and skin. The most common type of amoebiasis is hepatic amoebiasis.
E. histolytica is a monogenetic parasite and its only host is human.

Question 9.
What is AIDS? How can it be prevented?
Answer:
AIDS or Acquired Immuno Deficiency Syndrome refers to a disorder in which the immunity of body is decreased due to reduction of T-helper cells that activate other lymphocytes too.
It’s caused due HIV or Human Immuno Deficiency virus.

Prevention of AIDS

• Sterlise all surgical instruments before use.
• The transfusion of blood should be subjected to HIV test.
• Infected mother should avoid pregnancy otherwise, it may also transmit to child.
• Heterosexual activites should be prohibited.
• Motivate to use condoms during sexual activities.
• Proper medical dispose off should be established.

Question 10.
What is diabetes mellitus ? How can it be controlled ?
Answer:
The increased level of blood sugar in human body due to hyposecretion of insulin hormone leads to a condition called hyperglycemia. Prolonged hyperglycemia leads to diabetes mellitus characterised by high sugar, weight loss and production of excess urine. It is an acquired non-communicable disease of humans.
Diabetes can be kept under control by changing the diet to sugar free, administration of insulin hormone through injections, etc.

Question 11.
What are carcinogen?
Answer:
Causes of Cancer:
The agents which cause cancer, are called carcinogens.
Cancer can be induced by either physical, chemical or biological agents.

1. Physical agents These are ionising radiations like X-rays, Y-rays and the non-ionising rays like UV-rays which can cause DNA damage leading to neoplastic transformation.
2. Chemical agents These are tobacco smoke, benzene fumes, arsenic, hormones and aflatoxin, etc.
3. Nutritional agents Deficiency of some nutrients like vitamins, minerals and proteins causes cancer.
4. Biological agents Many cancers are caused by viruses. The association of Hepatitis-B and primary liver cancer has been established.
5. Mechanical factors Trauma, irritation and severe friction have been identified to cause malignancy.
6. Host factors These include age, sex, marital status, race, socio-economic status, customs and habits of the host.
7. Environmental factors These include radiation, air pollution, diet, drugs and social environment.
8. Genetic factors All factors have a genetic basis and are caused by genetic transformations of cells.

Question 12.
What STDs stand for? Explain with examples.
Answer:
STD stands for sexually transmitted diseases, which are transmitted through sexual intercourse with infected persons. For example AIDS, syphilis, trichomoniasis.

1. Syphilis is caused by bacteria named Treponema pallidum. Initially, it leads to ulcers on the genitalia followed by skin lesions, rashes and swollen joints.
   It is cured by taking penicillin or tetracycline as antibiotics.
2. AIDS is caused by human immunodeficiency virus. It leads to decreased immunity of the patient along with many other symptoms like lethargy, weight loss, nausea, fiver. Although, AIDS is incurable yet a drug zidovudine (AZT) is used to treat this.
3. Trichomoniasis is a STD caused by Protozoa Trichomonas vaginalis. It infects both male and female causing foul smelling, yellow discharge and burning sensation in females and pain and burning sensation in males. It is usually treated by metronidazole in both the cases.

Question 13.
What is cancer? Give its causes.
Answer:
It is defined as an uncontrolled growth or proliferation of cells without any differentiation. Cancer cells divide repeatedly in an uncontrolled manner. It has an ability to invade other tissues or organs, cause necrosis or programmed cell death, i.e. apoptosis.

In normal cells, cell growth and differentiation is highly controlled and regulated. Normal cell shows a property called contact inhibition by virtue of which contact with other cells stops their uncontrolled growth. Cancerous cells appear to have lost this property. As a result, these cells continue to divide to produce a mass of cells called tumour or neoplasm.

Causes of Cancer
The agents which cause cancer, are called carcinogens.
Cancer can be induced by either physical, chemical or biological agents.

1. Physical agents These are ionising radiations like X-rays, v-rays and the non-ionising rays like UV-rays which can cause DNA damage leading to neoplastic transformation.
2. Chemical agents These are tobacco smoke, benzene fumes, arsenic, hormones and aflatoxin, etc.
3. Nutritional agents Deficiency of some nutrients like vitamins, minerals and proteins causes cancer.
4. Biological agents Many cancers are caused by viruses. The association of Hepatitis-B and primary liver cancer has been established.
5. Mechanical factors Trauma, irritation and severe friction have been identified to cause malignancy.
6. Host factors These include age, sex, marital status, race, socio-economic status, customs and habits of the host.
7. Environmental factors These include radiation, air pollution, diet, drugs and social environment.
8. Genetic factors All factors have a genetic basis and are caused by genetic transformations of cells.

Question 14.
Write down different types of cancer.
Answer:
Types of Cancer
On the basis of localisation, cancer is divided into several main types

1. Carcinoma Cancer of epithelial tissues and their derivatives, e.g. breast cancer, lung cancer.
2. Sarcoma Cancer of connective tissues, e.g. bone cancer, muscle cancer, cancer of lymph nodes.
3. Lymphoma Excessive production of lymphocytes by lymph nodes and spleen, e.g. Hodgkins disease, multiple myeloma and other immunoproliferative diseases.
4. Leukemia Cancer of blood forming tissues like stem cells in bone marrow. There is increase in WBC number which destroys the cells of other organs, commonly known as blood cancer.

Some Other Types of Cancer

• Adenoma Cancer of glands.
• Lipoma Cancer of adipose tissue.
• Glioma Cancer of glial cells of central nervous system.
• Myoma Cancer of muscular tissue.
• Melanoma Cancer of pigmented epithelium of skin.

Question 15.
What is the causative agent of gonorrhoea? What are its symptoms and treatment?
Answer:
Gonorrhoea is caused by bacteria Neisseria gonorrhoea. It resides in the genital tube and produces pus-containing discharge, pain around genitalia and burning sensation during urination. It can be cured through appropriate medicines like penicillin or ampicillin.

Question 16.
Explain oncogenes.
Answer:
Oncogenes encode oncoproteins which promote the loss of growth control and the transformation of cell to a malignant cells. Cancer causing viruses are called oncoviruses and their genes as v-onc (viral protooncogenes). These viral oncogenes have homologous regions in human genome.

The homologous genes are called cellular protooncogenes (c-onc). Nearly 100 protooncogenes are known and these are involved in cell functions. The sudden-change, i.e. mutation in protooncogenes induces abnormal functioning and tumour formation.
Viral protooncogenes constitutes another class of factors transforming protooncogenes into expression ready cellular oncogenes. Which encodes for abnormal proteins known as oncoproteins.
The name of oncogenes are derived from the names of the host viruses are v-src, c-myc, etc.

Question 17.
Explain tumour suppressor gene or antioncogene.
Answer:
Tumor suppressor gene or antioncogene are the genes which protects a cell form the formation of cancerous cells.
When these genes are characterised by mutations, it leads to reduction in its function and cell becomes prone to cancer along with many genetic changes. Tumor suppressor genes are categorised into caretaker gatekeeper and landscaper genes.

Question 18.
Write a note on parasite.
Answer:
Parasite are the organism which lives on other organisms called host and derive their nutrition from the host. They are dependent on host for their survival and they have to be in host, to live, grow and multiply. The one which lives on the surfaces of earth are called ectoparasite, while which lives in the organisms are called endoparasites.

Question 19.
Explain incubation period of malaria parasite.
Answer:
The incubation period in malaria is defined as the period between infection and beginning of the symptoms. It typically lasts between 10 days to 4 weeks.
The incubation period is affected by the type of Plasmodium parasite responsible for the infection. If a patient is given antimalarial drugs which prevent the spread of disease, it can also increase the incubation period by weeks or months.

Question 20.
What kind of physical changes are characteristic of adolescence?
Answer:
Physical changes Adolescence is a period of active growth and sexual maturity. Growth becomes once apparent with an increase in body size, height and weight due to continued secretion of growth and sex hormones (FGH and LH).

Under the influence of these hormones, the body begins to develop secondary sexual characters in males like beard growth, change in voice pitch, etc., and females such as initiation of menstruation, enhanced breast size, etc.

Question 21.
What kind of psychological changes characterise adolescence?
Answer:
Psychological changes Adolescence shows changes in behaviour, emotions and attitude.
For example, difficulty in accepting parental decisions, coping with studies, competition, increased need for money, keeping bad company, etc.

Question 22.
Which is the most common skin problem that affects the youth in adolescence? What are its causes ?
Answer:
The most common skin problem that occurs during youth or teen years is acne.
During puberty hormone level increases and the skin starts releasing more oil (sebum). When this mixes with dead cells of the skin, it closes the pores and causes swelling, redness and pus.
Few medical conditions such as polycystic ovary syndrome, cushing’s syndrome can also lead to acne.

Question 23.
What is the cause of alcoholism?
Answer:
The dependence on alcohol or when a person becomes addicted to alcohol is called alcoholism. It is a result of combination of genetic, psychological, environmental and social factors described below

• People become addicted to alcohol to relieve stress and the deal with the pressure in their families or workplace.
• Disorders like anxiety, depression, bipolars disorders or other medical issue can increase the risk of alcoholism.

Question 24.
What are the effects of alcoholism in the body?
Answer:
Effects of Alcohol

1. High dose of alcohol, i.e. more than 30 ml acts as an intoxicant and affects the functioning of CNS.
   Alcoholism damages internal organs like liver, as alcohol is converted to acetaldehyde then to fat in liver. This fat begins to deposit in body and cause cirrhosis.
2. It many also cause hepatitis and liver cancer.
3. Increased consumption of alcohol per day dilates the blood vessels and it leads to hardening of blood vessels. This causes bradycardia and myocardiopathy.
4. Alcohol decreases ADH secretion and this may cause dehydration.
5. Drinking alcohol makes the person unusually aggressive and also, affects this judgement, coordination, alterness, vision and responsiveness.
6. Excessive intake of alcohol affects the behaviour of an individual.

Question 25.
What are the moral and social implications of drinking?
Answer:
Social and Moral Implications of Addiction

• Habitual drinking creates differences in the family. The addict cause public misdemeanour and misbehave hence is isolated from society as drinking is considered a social evil.
• Family status declines due to approaching poverty.
• Such individuals become violent suicidal, antisocial and- lazy.
• Drug and alcohol addicts develop habits like stealing, burrowing money for fulfilling their addiction.

Question 26.
What are the reasons of drug abuse by the youth?
Or
Mention the causes of drug abuse.
Answer:
Serious effects of drug abuse are

1. Academic performance decreases.
2. Frequent absence from school or college.
3. Isolation, fatigue, depression and aggressiveness occurs in behaviour.
4. No coordination with family members and friends.
5. Frequent fluctuations in weight.
6. Intravenous drug intake leads to risk of AIDS and hepatitis-B.
7. Excess use of alcohol or drug damages the nervous system and causes liver cirrhosis or cancer.
8. During pregnancy in females, drugs affect foetus seriously.

Question 27.
Write briefly on the main classes of drugs in use.
Answer:
Drugs are placed into one of three classes A, B or C under the misuse of drugs act 1971.
A drug class is the set of similar action placed under same group.
Class-A includes heroin (diamorphine), cocaine, methadone, LSD, ecstasy and magic mushrooms.
Class-B includes amphetamines, barbiturates, codeine, cannabis, cathinones and synthetic cannabiroids.
Class-C includes benzodiazepines (transquilisers), ketamine, anabolic steroids and Benzylpiperazines (BZP).

Question 28.
What are the withdrawal symptoms that are seen after drug abuse?
Answer:
The withdrawal symptoms of alcohol and,drug abuse are-

1. Hallucination
2. Fits
3. Tremors

The treatment of drug abuse includes

1. Use of detoxifying drugs like diazepan, vitamin-B, chlordizepoxide, apomorphine.
2. Use of antioxidants like disulfiram, cephalosporin, metronidazole.

Question 29.
What are the social and moral implications of drug abuse?
Answer:
Social and Moral Implications of Addiction

1. Habitual drinking creates differences in the family. The addict cause public misdemeanour and misbehave hence is isolated from society as drinking is considered a social evil.
2. Family status declines due to approaching poverty.
3. Such individuals become violent suicidal, antisocial and- lazy.
4. Drug and alcohol addicts develop habits like stealing, burrowing money for fulfilling their addiction.

Question 30.
What are the effects of tobacco use in the body?
Answer:
Dried and crushed leaves of Nicotiana tabacum and Nicotiana rustica are used to make tobacco. It can induce lung cancer, bronchitis, emphysema, coronary heart disease, cancer of throat, oral cancer, cancer of urinary bladder, etc.
Smoking leads to the increase in the content of carbon monoxide in the blood which reduces the concentration of haemoglobin bound oxygen. This leads to oxygen deficiency in the body

Question 31.
What kind of diseases affect the body in smoking?
Answer:
Major diseases which affect the body in smoking are

1. Stroke As smoking affects the arteries of a person, it can trigger stroke.
2. Lung cancer It is the most common type of cancer caused due to smoking.
3. Chronic obstructive pulmonary disease It is an obstructive lung disease which leads to difficulty in breathing. It leads to early death.
4. Asthma Smoking irritates air passages and can trigger sudden and severe asthma attacks.
5. Cancer Over ten other types of cancer including colon, liver, cervix, stomach and pancreas are caused due to smoking.

Question 32.
What is mental illness?
Answer:
Mental illness is a state of emotional and psychological well being of a person which allows him/her to attain his/ her physical cognitive and emotional capabilities.

Question 33.
What are the causes of mental illness?
Answer:
The causes of mental illness are depression, obsessive, compulsive disorder, mood disorder, attention deficiency disorder, sleeplessness, self destructive actions, loss of memory, etc.

Question 34.
What are the different types of mental disorders seen in man?
Answer:
The different types of mental disorders are

1. Psychosis
2. Neurosis
3. Schizophrenia
4. Phobia
5. Epilepsy
6. Parkinson’s disease
7. Alzhaimer’s disease.

Differentiate between the following

Question 1.
Amoeba and Entamoeba.
Answer:
Differences between Amoeba and Entamoeba are as follows

Amoeba	Entamoeba
Amoeba are a large class of unicellular organisms that are eukaryotic.	Entamoeba are a genus of amoeba that live on other organisms.
They move by means of pseudopodia.	They are usually a part of normal fauna and live in symbiotic association.

Question 2.
Filaria and Malaria.
Answer:
Differences between filaria and malaria are as follows

Filaria	Malaria
It is a parasitic disease caused by infection of roundworms.	Malaria is caused by parasitic protozoan to Plasmodium.
The symptom includes edema which causes thickening of skin and underlying tissues.	The symptoms include headache, fever, joint pain, retinal damage, etc.
Wuchereria bancrofti is the parasite which causes filariasis.	Female Anopheles mosquito transmits a mature infective form to the host.

Question 3.
Communicable Diseases And Non-Communicable Diseases
Answer:
Differences between communicable diseases and non-communicable diseases are as follows

Communicable diseases	Non-communicable diseases
These disease do not remain confined to the person who suffer from them.	These disease remain confined to the person who suffer from them.
These are transmitted from infected person to other persons directly or indirectly by any causative organisms.	They are not transmitted from infected person to other persons except for genetic transmission in some case.
e.g. viral diseases (influenza, mumps, AIDS, smallpox) bacterial diseases (cholera,typhoid, TB,tetanus,etc.)	e.g, diabetes, cancer, arthritis, cardiovascular diseases, etc.

Question 4.
Magna and Minuta stage.
Answer:
Differences between magna stage and minuta stage are as follows

Magna stage	Minuta stage
It is the active stage of pathogenic stage of Entamoeba histolytica also called trophozoite.	It is the non-pathogenic and non-motile and non-feeding form.
It resembles Amoeba in its active form and cytoplasm is divisible into ectoplasm and endoplasm.	It lives in the lumen of intestine and may develop into magna by penetrating intestinal wall.
It measures 20-30 p in diameter.	It measures about 12-15 pt in diameter.

Question 5.
Infection and Infestation.
Answer:
Differences between infection and infestation are as follows

Infection	Infestation
Infection is caused by microorganisms or germs or viruses.	Infestation refers to the infection by larger and more complete organisms like pests or parasites.
The germs or microorganisms which causes infection usually grow inside the body and cause illness.	Infestation is commonly used in context to one organism present on external surface.

Question 6.
Carcinoma and Sarcoma.
Answer:
Differences between carcinoma and sarcoma are as follows

Carcinoma	Sarcoma
The cancer of epithelial epidermal tissues and their derivatives.	The cancer of connective tissues is called sarcoma.
It usually includes cancer of lungs, breast, etc.	It includes bone, muscle or cancer of lymph nodes.
They spread throughout the body by blood and lymph.	They spread through nodules.
They occur primarily in people over 50 years of age.	It affects both young and old people.

Question 7.
Benign tumour and Malignant tumour.
Answer:
Differences between benign tumour and malignant tumour are as follows

Benign tumour	Malignant tumour
It remain confined to the site of its origin.	It is not confined to the tissues.
It may grow in size but does not spread to other parts of the body.	They are carried to other parts of the body by blood or lymph.
It is enclosed in connective tissue.	It is not enclosed in any specific tissue.

Question 8.
Sporogony and Gamogony.
Answer:
Differences between sporogony and gamogony are as follows

Sporogony	Gamogony
It is an asexual stage which produces haploid sporozoites.	It is a sexual phase followed by sporogony which produces a diploid zygote.
The oocyte so formed are liberated into haemolymph of mosquito.	The zygote elongates into motile worm-like vermicule which penetrates the stomach wall, enclosed itself in a cyst and grows in size.

Question 9.
Innate immunity and Acquired immunity.
Answer:

Innate immunity	Acquired immunity
It is a non-specific type of immunity.	It is a pathogen specific immune response.
It is inherited from parents and protects the child since birth.	It is acquired after the birth of an individual, during its lifetime.
It provides barrier against the entry of pathogen in the body.	It produce B-lymphocytes and T-lymphocytes. It also produces primary and secondary types of immune response.

Question 10.
Cell-mediated immunity and Humoral immunity.
Answer:
Differences between cell-mediated immunity and humoral immunity are as follows

Cell-mediated immunity	Humoral immunity
It is the type of immunity which is mediated by T-lymphocytes to produce antibodies.	It is mediated by antibodies present in blood and lymph.
It provides immunity against all pathogens including fungi and Protozoa.	It provides immunity against virus and bacteria.
It shows reaction against organ transplantation.	It does not react against organ transplantation.

Question 11.
Vaccination and Immunisation.
Answer:
Differences between vaccination and immunisation are as follows

Vaccination	Immunisation
Vaccination is the process of introducing the body to a form of virus.	Immunisation is the process of body building up natural defence against bacteria.
It is injected in the form of drops.	It does not require administering as its the natural capacity of body.

Long Answer Type Questions

Question 1.
What are pathogens ? Classify diseases and give a note on this.
Answer:
Pathogens:
Infectious disease causing agents are called pathogens and their disease causing capacity is known as pathogenicity or virulence. Most of the pathogens are parasites. They can cause harm to the organism (host) by either living in (as endoparasites) or on them (as ectoparasite). These disrupt the normal physiology of organisms, either plants or animals and express a number of symptoms. The human body contains many natural defence mechanisms against some common pathogens. Certain pathogens have been found to be responsible for massive casualities.

Despite many medical advances for safeguarding human beings from infections by pathogens through the use of vaccines, antibiotics and fungicides, pathogens continue to threaten human lives. They can enter our body by various means s.uch as air, water, food, etc., and can multiply and interfere with the normal vital activities of the body, thus, resulting in the morphological and functional damage.

Classification of Pathogens:
Major classes of pathogens which cause disease, produce toxin and induce immunosuppression in the most are given below

Classes of Pathogens	Examples
Viruses	Adenovirus, picorna virus, retrovirus, papovavirus, polyma virus, etc.
Bacteria	Mycobacterium, Streptococcus, Shigella and Salmonella.
Fungi	Saprophytic pathogenic fungi.
Prions	Protein pathogens that cannot contain nucleic acids.
Parasites	Protozoan and helminth parasites.

Question 2.
Give the symptoms, infection, prevention and control of typhoid.
Answer:
Typhoid:
It is also known as enteric fever and is caused by bacterium Salmonella typhi. It is common in developing countries, where it affects 21.5 million persons every year (1 million in India).

Symptoms and Diagnosis
The incubation period of parasite is about 1-2 weeks and the duration of illness is about 4-6 weeks. The symptoms of typhoid include fever (39-40°C), lethargy, stomach pain, headache, poor appetite, diarrhoea or constipation and rose spots on abdomen. The intestinal
perforation or bleeding may occur in severe cases, which may lead to death. The reccurrence (relapsing) of disease is observed in 10% of patients. Typhoid is diagnosed by WIDAL test. ”

Infection and Transmission
Salmonella typhi invades human intestine through contaminated water or food, from where they are carried by white blood cells to the liver, spleen and bone marrow. They multiply in these organs and re-enter the bloodstream. At this stage, a person begins to develop symptoms like fever. Through the bloodstream the bacteria further invade various organs like gall bladder, biliary system, lymphatic tissues and ultimately pass into the intestinal tract. From here the bacteria can be diagnosed in cultures of stool.
The disease may be transmitted through carriers also. These are those person who recovered from typhoid but continue to carry the bacterial infection.

Treatment
Treatment includes antibiotics like fluoroquinolones, ceftriaxone and azithromycin. But, Salmonella develops resistance to multiple antibiotics. The emergence of multi-drug resistant typhoid has complicated the treatment procedure, especially in those who have acquired infection from South Asia. Therefore, antibiotic susceptibility test in helpful in deciding an appropriate therapy pathway.

Vaccination
The following vaccines are given in the treatment of typhoid

Vaccine	Type	Dose
Vi antigen	Inactivated vaccine injectable	A single dose of 0.5 ml administered intramuscularly on thighs and arms.
Oral ty21a	Oral live vaccine	Course of 3 capsules given on alternate days.

Prevention and Control
There are several ways through which bacterial infection of typhoid can be avoided

1. Maintain personal hygiene.
2. Consume thoroughly washed and properly cooked vegetables and fruits.
3. Drink packaged water with statutory quality or boiled water. Bottled carbonated water is also used to consume and it is safer than other.
4. Vaccination against typhoid can be done.

Question 4.
What are acquired and innate immunity?
Discuss the mechanical and chemical barriers of innate immunity.
Answer:
Innate Immunity (Inborn)
It is the type of immunity which is present from birth and is inherited from the parents. That’s why it is also called as natural immunity. It is non-specific in nature as it involves general protective measures against any invasion. Innate immunity provides the early lines of defense against pathogens. The principal components of innate immunity that act as barrier system to prevent the entry of pathogens are given below
1. Mechanical barriers
2. Chemical barriers
3. Phagocytosis
4. Fever
5. Inflammation
6. Acute phase proteins
7. Natural Killer (NK) cells

1. Mechanical or Physical Barriers:
They prevent entry of microorganisms in the body, e.g. skin, mucous coating of epithelium lining the respiratory, gastrointestinal and urogenital tracts. These barriers are also called as first line of defence.

• Skin It is outer and tough layer of epidermis that consists of insoluble protein called keratin. It prevents the entry of bacteria and viruses. The periodical sheding off process of skin removes any clinging pathogen.
• Mucous membrane The gastrointestinal tract, urinogenital tract and conjuctiva are lined by mucous membrane.

This membrane secretes mucus which entraps microbes, dust or any foreign particles and finally propelled them out through tears, saliva, coughing and sneezing.

2. Chemical or Physiological Barriers
It includes certain chemicals which dispose off the pathogens.
These are given below

1. Acid of stomach, kills the ingested microorganisms by secreting acid gastric secretion (pH 1.5 – 2.0).
2. Low pH of sebum (i.e. 3.0-5.0) forms a protective film over the skin that inhibits growth of many microbes.
3. Lysozyme is a hydrolytic enzyme present in all mucous secretions like tears, saliva and nasal secretions. It attacks bacteria and dissolves their cell walls.
4. Gastro and duodenal enzymes secrete proteases and lipases. These enzymes digest a variety of structural and chemical constituents of pathogens, e.g. gastric acids easily inactivate rhinoviruses.
5. Mothers milk Lactoferrin and neuraminic acid are antibacterial substances present in human milk to fight against Staphylococci.
6. A group of proteins produced by virus infected cells, i.e. interferons induces a generalised activated state in neighbouring uninfected cells.
7. Humans and some other animals secrete an number of antimicrobial peptides such as defensins. One micrometre thick biofilm of defensins protects the skin from microbial assault.

3. Phagocytosis
When pathogens or microbes penetrate the skin or mucous membrane certain cell types surge towards the site of infection. These can be neutrophils, monocytes and macrophages which engulf the pathogens to form a large intracellular vesicle called phagosome.
The phagosome fuses with lysosome to form phagolysosome. The secretion of lysosomal enzymes digests bacterial cells. The useful products remains in the cell while the waste is egested out of the cell. Therefore, these phagocytes are also known as second line of defence.

4. Fever
It may be brought about by endotoxins or proteins (cytokines) produce by pathogens called endogenous pyrogens.
When enough pyrogens are produced, then there is rise in temperature which strengthens the defence mechanism to inhibit the growth of microbes. Fever is a symptom of an internal diagnoses of the cause of infections.

5. Inflammation
It is a defensive response of the body to tissue damage.
It is characterised by abrasions, chemical irritations, heat, swelling, redness and pain. Inflammation in a non-specific response of the body to injury. It is an attempt to dispose off microbes, toxins or foreign material at the site of injury by macrophages to prevent their spread to other tissues and to prepare the site for tissue repair. Thus, it helps to restore tissue homeostasis.

Broken mast cells release histamine, bradykinin, etc., which cause dilation of capillaries and small blood vessels. As a result more blood flows in these areas making them red and warm. Therefore, the accumulation of this results into tissue swelling (oedema).
After few days, due to phagocytosis, a cavity containing necrotic tissue and dead bacteria is formed. This fluid mixture is called pus.

6. Acute Phase Proteins
The chemical messenger of immune cells called cytokines are important low molecular weight proteins. These heterogenous proteins stimulate or inhibit the differentiation, proliferation or function of immune cells and also certain viral infections.

7. Natural Killer (NK) Cells
These are non-phagocytic granular lymphocytes which are present in spleen, lymph nodes and bone marrow.

Then can produce perforins or cytolysin which lyses the vi ral infected cells.
These cells can kill a range of tumour cells without any antigen specificity.

Mechanism of Active Aquired immunity
Active acquired immunity is more effective and superior than passive immunity. It occurs in two different forms called cell-mediated and humoral immune responses.
(i) Cell-Mediated Immune Response or Cell-Mediated Immunity (CMI) It is the type of acquired immunity mediated by T-lymphocytes. Activated T-lymphocytes undergo proliferation and differentiate into different types of effector cells, such as T-helper (TH) and T-cytotoxic or killer (Tc) lymphocytes and memory T-lymphocytes (TM). TM confers a long term memory against the invading pathogen. Tc /TK cells directly kill or destroy antigens or antigen bearing pathogens. TH cooperates with B-lymphocyte and triggers its transformation into a plasma cell.

(ii) Humoral response or Antibody-Mediated Immunity (AMI) It is mediated by antibodies present in blood and lymph. Immunoglobulins or antibodies are glycoproteins produced in the body by B-cells in response to an antigen, e.g. IgA. IgG, IgM, IgE and IgD.

B-cells multiple in large number and transform into larger cells called plasma cells or plasmocytes. The transformation into plasma cells in assisted By T-Helper cells (TH). These antibodies destroy antigens by specific antigen-antibody interaction.

Question 5.
Mention the factors causing cancer. Add a note on diagnosis and prevention of cancer.
Answer:
Causes of Cancer
The agents which cause cancer, are called carcinogens.
Cancer can be induced by either physical, chemical or biological agents.

1. Physical agents These are ionising radiations like X-rays, v-rays and the non-ionising rays like UV-rays which can cause DNA damage leading to neoplastic transformation.
2. Chemical agents These are tobacco smoke, benzene fumes, arsenic, hormones and aflatoxin, etc.
3. Nutritional agents Deficiency of some nutrients like vitamins, minerals and proteins causes cancer.
4. Biological agents Many cancers are caused by viruses. The association of Hepatitis-B and primary liver cancer has been established.
5. Mechanical factors Trauma, irritation and severe friction have been identified to cause malignancy.
6. Host factors These include age, sex, marital status, race, socio-economic status, customs and habits of the host.
7. Environmental factors These include radiation, air pollution, diet, drugs and social environment.
8. Genetic factors All factors have a genetic basis and are caused by genetic transformations of cells.

Cancer Detection and Diagnosis
Cancer can be detected by the following well-known methods

1. Blood and bone marrow tests are conducted to know number of cell counts, e.g. WBC count in leukemia.
2. Biopsy of a piece of suspected tissue is done by cutting thin sections, staining and examining them under the microscope.
3. Radiography by X-rays is done to detect cancer of the internal organs.
4. Computed tomography using X-rays is done to generate a 3-D image of internal tissue.
5. Magnetic Resonance Imaging (MRI) involves the use of non-ionising radiation and strong magnetic field to detect pathological and physiological changes in living tissue.
6. Monoclonal antibodies against cancer-specific antigens are also used for cancer detection. These are homogenous immunological reagents of defined specificity.
7. Mammography for detection of breast cancer.
8. Fine Needle Aspiration Cytology (FNAC)
9. PAP test (cytological staining) used for detection of cervix cancer.

Prevention
According to WHO, the prevention of cancer is ‘the elimination of or protection against, factors known or believed to be involved in carcinogenesis (formation cancerous tumours) and the treatment of precancerous conditions’.
This implies that cancer cannot be cured at the late-stage so it is better to adopt some preventive measures be for its initiation and progression.

The preventive measures are

1. Educate people to go for early diagnosis and early treatment for better chance of survival.
2. Motivate people to know about the oncogenic effects of tobacco.
3. Prohibit the advertisements of cigarettes and drugs that may increase the chances of cancer.
4. Maintain personal hygiene.
5. Control environmental pollution by taking major steps.
6. Reduce amount of radiation.
7. Organise occupational health programmes.
8. Take treatment of cancerous.

Symptoms of Initiation and Progress of Cancer

1. A hump or hard area in the breast.
2. A change in wart or mole.
3. A persistent change in digestive and bowel habit.
4. A persistent cough or hoarseness, excess loss of blood at the monthly period or loss of blood outside the usual dates.
5. Blood loss from any natural orifice.
6. A swelling or sore that does not get better.
7. Unexplained loss of weight.

Question 6.
Give the structure of HIV. Give an account of infection, control and prevention of AIDS.
Answer:
Structure of HIV:
The virus belongs to retrovirus family and is roughly spherical-shaped with a diameter of 90-120 nm. The core has two single-stranded RNA enveloped with conical capsid mode up of viral proteins P24.
Each RNA fdament is segmented into two identical filaments and associated with nucleo-capsid proteins and enzymes like reverse transcriptase enzyme and integrase.

Reverse transcription in HIV

Between the capsid and matrix of the virus proteases and other proteins are present. The matrix consists of lipid bilayer of host cell membrane and projecting knob like glycoprotein spikes. It contains two proteins called gpl20 and gp 41. These proteins are required for anchoring to the host cell and entering into it.

Structure of human immunodeficiency virus

Infection:
HIV infects CD 4 T-lymphocytes and dendritic cells. It anchors to the surface of host cell by adsorption assisted by the glycoprotein. This release the capsid and then the begins the replication of retrovirus begins in the host cell. The HTV lefts untreated then it progresses in three stages

1. Acute infection Patient develops some symptoms like flu, fever, swollen glands, soar throat, rash, muscle and joint pain and headache, within 2-4 weeks and HIV infection. This stage is at higher risk of transmitting virus through coitus and injectable drugs using contaminated needle.
2. Clinical latency stage In this case, virus replicates in host cell without expressing symptoms. If patient undergoes retroviral therapy he may live for decades. If he is not on the therapy, then the latency stage lasts on an average for ten years.
3. Typical (AIDS) stage At this stage, HIV infection acquires its full strength and damages the immune system badly. The value of CD 4 lymphocytes fall below 200 per cubic mililitre of blood. The infected person contracted many other bacterial and fungal diseases.

Some of the prevalent symptoms at this stage are

1. Weight loss and unexplained tireness
2. Chronic diarrhoea
3. Pneumonia
4. Prolonged swelling of the lymph glands of armpit, groin and neck.
5. Recurring fever with night sweats.
6. Persistent cough
7. Mouth and skin problems
8. Recurrent infections
9. Sores of the mouth, anus and genitals .
   Without treatment, people who progress to AIDS survive about three years.

Diagnosis:
There are several methods for the diagnosis of HIV infection such as viral culture, Enzyme Linked Iramuno Sorbent Assay (ELISA), PCR test, Western blotting, etc. Out of these, ELISA and Western blotting are widely used.

Prevention:
There is no effective treatment developed to treat AIDS. Therefore, some preventive measures are recommended to prevent its infection

The preventive measures are as follows

1. Sterlise all surgical instruments before use.
2. The transfusion of blood should be subjected to HIV test.
3. Infected mother should avoid pregnancy otherwise, it may also transmit to child.
4. Heterosexual activites should be prohibited.
5. Motivate to use condoms during sexual activities.
6. Proper medical dispose off should be established.

Government of Indian launched national AIDS control board, national AIDS committee, national AIDS control organisation, etc., to create awareness among people about HIV transmission and progression of AIDS.