CHSE Odisha Class 12 Biology Solutions Chapter 11 Microbes in Human Welfare

Odisha State Board CHSE Odisha Class 12 Biology Solutions Chapter 11 Microbes in Human Welfare Textbook Questions and Answers.

CHSE Odisha 12th Class Biology Chapter 11 Question Answer Microbes in Human Welfare

Microbes in Human Welfare Class 12 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Multiple choice questions

Question 1.
In curd making, …………. is useful in coagulation of milk protein. (Lactobacillus, Saccharomyces, Penicillium, Aspergillus)
Answer:
Lactobacillus

Question 2.
Antibiotic streptomycin is obtained from ……….. (Streptomyces griseus, S. aureofaciens, S. nouresi, Saccharomyces cerevisiae)
Answer:
Streoptomyces griseus

Question 3.
Citric acid is produced when fermentation is caused by …………. (Lactobacillus, Aspergillus sp., Penicillium sp., Acetobacter sp.)
Answer:
Aspergillus sp.

Question 4.
Lipase enzyme is produced by the activity of …………. (Trichoderma viride, Rhizopus sp., Aspergillus sp., Saccharomyces cerevisiae)
Answer:
Rhizopus sp.

Question 5.
In pest control of crop plants ……………. has pesticidal properties, (baculovirus, papilloma virus, pox virus, Rhizobium)
Answer:
baculovirus

Express in one word only

Question 1.
What is called the process of heating and cooling of milk for inactivation of bacteria?
Answer:
Pasteurisation

Question 2.
What is called the secretions of microorganisms which are toxic to pathogenic bacteria?
Answer:
Antibiotics

Question 3.
What is the commercial name of acetic acid?
Answer:
Vinegar

Question 4.
What is called the accumulated microorganisms and organic matter in the treatment of sewage?
Answer:
Sludge

Question 5.
What is the major component of biogas?
Answer:
Methane

Question 6.
What can be called the natural pest killing agent other than artificial chemical?
Answer:
Biopesticides

Question 7.
What is called the association between Rhizobium in the root system of legumes?
Answer:
Symbiotic association

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

Question 1.
Antibiotic tetracyclin is obtained from Penicillium notatum.
Answer:
penicillin

Question 2.
In biogas, methane is produced due to the activities of nitrogen-fixing bacteria.
Answer:
methanogenic

Question 3.
The first antibiotic extracted from bacterial culture is nystatin.
Answer:
streptomycin

Question 4.
Industrial production of organic acids through microbial cultures is due to the oxidation process by bacteria.
Answer:
fermentation

Question 5.
Acetic acid is produced by Lactobacillus sp.
Answer:
Lactic acid

Fill in the blanks

1. In biogas production ………… bacteria are used.
Answer:
methanogenic

2. BGA used in biological nitrogen-fixation are called ………….. bacteria.
Answer:
cyano

3. Ethanol obtained by ………….. fermentation is used in industry.
Answer:
microbial

4. Acetobacter converts ……………. to vinegar by aerobic fermentation of legumes.
Ans.
ethyl alcohol

Short Answer Type Questions

Write notes on the following with atleast 3 valid points

Question 1.
Biogas
Answer:
It is a complex mixture of gasese like CH₄,CO₂, H₂, etc., that is produced by anaerobic digestion of biomass. It is used as fuel.

Question 2.
Biopesticides
Answer:
These are biodegradable, highly pest specific biological agents that are used to control pest population without harming the environment.

Question 3.
Biofertilisers
Answer:
These are the preparations containing microorganisms that help the plants to uptake various nutrients in utilisable form, e.g. Rhizobium, BGA, etc.

Question 4.
Microbes in industry.
Answer:
Industrial use of microbes includes the production of beverages, antibiotics, etc., that are useful for the human. The large scale production of these products is carried out in bioreactors using the appropriate microbes, e.g. butyric acid is derived from Clostridium and terramycin is derived from Streptomyces rimosus.

Question 5.
Microbes in antibiotics production.
Answer:
The term ‘antibiotics’ was coined by Waksman (1942), and it is derived from the Greek words Anti-against and bios-Yiit, together they mean ‘against life’ (with reference to disease causing organisms). Antibiotics are the chemical substances, produced by some microbes that can kill or retard the growth of other disease causing microbes.

The first antibiotic was obtained from the species of Penicillium notatum in 1928 by Sir Alexander Fleming and it was named Penicillin.

Question 6.
Microbes in sewage treatment.
Answer:
Sewage refers to the municipal waste water generated everyday in cities and towns. Human excreta is the major component of it. It contains large amounts of organic matter and microbes, out of which many are pathogenic. So, it cannot be discharged directly into natural water bodies like rivers, streams, etc.

Differentiate between two words in the following pairs of words

Question 1.
Chemical fertilisers and Biofertilisers.
Answer:
Differences between chemical fertilisers and biofertilisers are as follows

Chemical fertilisers	Biofertilisers
These are industry made products which are used to increase the output of a crop plant.	These are the microorganisms which increase the nutrient level of soil.
These are harmful and cause pollution to water bodies as well as ground water.	These are not harmful as they lead to nutrient enrichment in an organic way.

Question 2.
Synthetic pesticides and Biopesticides.
Answer:
Differences between synthetic pesticides and biopesticides are as follows

Synthetic pesticides	Biopesticides
These are not very specific, so harm non-targeted species.	These are highly specific, so do not harm non-targeted species.
They cause pollution.	They do not cause pollution.
Insects may become resistant, e.g. Heliothis, has become resistant to most insecticides.	Insects are not expected to develop resistance to biopesticides.
Harmful residues may often remain in food, fodder and fibres.	No harmful residues remain in food, fodder and fibres.

Question 3.
Baker’s and Brewer’s yeast.
Answer:
Differences between baker’s and brewer’s yeast are as follows

Baker’s yeast	Brewer’s yeast
Baker’s yeast is Saccharomyces cerevisiae. It is used in fermentation to prepare dough that is used to make bread, idli, dosa, etc.	Brewer’s yeast is also Saccharomyces cerevisiae, but a different strain. It is used to produce various alcoholic drinks by fermenting malted cereals and fruit juices.
In this, CO2 released during the process of fermentation gives the fluffy appearance.	In this, CO2 released does not cause any fluffy appearance.

Question 4.
Symbiotic nitrogen-fixation and Mycorrhizal nitrogen-fixation.
Answer:
Differences between symbiotic nitrogen-fixation and mycorrhizal nitrogen-fixation are as follows

Symbiotic nitrogen-fixation	Mycorrhizal nitrogen-fixation
It is a mutually beneficial association of bacteria with the plants for food and shelter.	It is a mutually beneficial association of fungus with the root of higher plants.
The most common is Rhizobium which resides in root nodules of leguminous plants and fixes nitrogen.	Members of genus Glomus form mycorrhizal association.

Long Answer Type Questions

Question 1.
Give a detailed account of industrial application of microbes.
Answer:
Industrial Products:
A variety of microbes are used to synthesise a number of products in large scale that are valuable to human beings, e.g., beverages, antibiotics, etc.
A microbe should have following characteristics for its application in industrial fermentation.

• It should be non-pathogenic and its raw materials should be cheap and easily available.
• It should have the ability to grow rapidly on suitable nutrients.
• It should have the ability to high yield of desired products consistently in a reasonable time.
• It should possess high levels of enzymes for rapid production of the end products.

Now-a-days a number of products are obtained on commercial level with the help of microbes. To accomplish this, microbes are grown in very large vessels called fermentors or bioreactors.
Some of the industrial products obtained using microbes are as follows

Antibiotics:
The term ‘antibiotics’ was coined by Waksman (1942), and it is derived from the Greek words Anti-against and bios-Yiit, together they mean ‘against life’ (with reference to disease causing organisms). Antibiotics are the chemical substances, produced by some microbes that can kill or retard the growth of other disease causing microbes.

The first antibiotic was obtained from the species of Penicillium notatum in 1928 by Sir Alexander Fleming and it was named Penicillin.

It was obtained at commercial scale by growing the microbe in fermentor. The medium used for growing microbe, contained a carbohydrate as energy source, mineral salts and corn steep liquor. The culture was kept under vigorous aeration to obtain the maximal production of ‘penicillin’. It was called the wonder drug as it was used during second World War to give relief to the wounded soldiers from pain and suffering.
Antibiotics and Their Sources

Antibiotic	Sources	Action
Penicillin	Penicillium chrysogenum, P. notatum.	Tonsilitis, sore throat, gonorrhoea.
Streptomycin	Streptomyces griseus	Pneumonia, tuberculosis and local infections.
Erythromycin	Streptomyces erythreus	Typhoid, diphtheria, whooping cough.
Terramycin	Streptomyces rimosus	Intestinal and urinary infections.
Tetracyclines	Streptomyces aureofaciens	Eye infections.
Chloramphenicol	S. venezuelae	Conjunctivitis.
Nystastin	S. nouresi	Candida infection.
Polymixin	Bacillus polymyxa	Antifungal.

The second antibiotic, streptomycin was obtained from the bacterium Streptomyces griseus. The bacteria were grown on culture medium containing glucose, soyameal and mineral salts at pH 7.4 -7-5.

The fermentation was carried out under submerged condition at 25-30°C for 5-7 days. Now-a-days industrial fermentation is used to produce several antibiotics against diseases which have earlier caused widespred destruction in the form of epidemics.

Alcoholic Beverages:
Earlier, people used to produce alcohol by fermentation. Later, another method was used for the same which included catalytic hydration of ethylene. In modern time, again fermentation process is used for the production of ethanol.

It is used for dual purpose, i.e. as chemical and as fuel. Sugar-beet, potatoes, corn, cassava and sugarcane, etc., are used as substrate for the production of ethanol.

Yeasts (like Saccharomyces cerevisiae, S. uvarum, S. carlsbergensis), Candida brassicae, C. utilis and bacteria (Zymomonas mobilis) are used for the production of ethanol at industrial scale. The type of alcoholic drink depends upon the raw material used for its production.

Beer is obtained by the fermentation of barley grains while wine is produced by grapes. This process of alcohol production is known as brewing. In this process, CO₂ is produced as a byproduct which is further used in bakery to provide sponginess to breads, cakes, etc.

Production of Organic Acids:
These are produced by the metabolic actions of microbes, i.e. microbial fermentation. Important organic acids producing organisms are listed below

Organic Acid	Microbes involved
Citric acid	Aspergillus niger and Penicillium sp. (fungi)
Acetic acid	Acetobacter aceti (bacteria)
Butyric acid	Clostridium butylicum (bacteria)
Lactic acid	Lactobacillus (bacteria)
Gluconic acid	Aspergillus niger and P. chrysogenum
Fumaric acid	Penicillium sp.

The methods of production of some organic acids are as follows

1. Acetic acid The production of acetic acid or vinegar occurs in two steps-preliminary fermentation and secondary fermentation. Former involves production of ethyl alcohol while later involves the production of acetic acid under aerobic conditions.
2. Lactic acid It is produced with the help of Lactobacillus. The starchy substances, e.g. corn starch, potato starch, molasses and whey, etc., are initially hydrolysed to obtain simple sugars. It is followed by fermentation under suitable environmental conditions.
3. Citric acid It is produced by the fermentation of beet molasses, sucrose, commercial glucose, starch hydrates, etc. Many fungi, bacteria and yeasts are used for the same.

Use of Organic Adds:
Organic acids are used as preservatives, flavour enhancers and flavouring agent. They are also used to prevent oxidation and turbidity of food products.

Production of Enzymes:
When microbes are grown in culture medium, they release various substances in the medium including enzymes. These substances can be extracted from the medium and can be used for various purposes like enzymes are used in pharmaceutical, food and textile industries. The quality and quantity of enzymes depend upon the microbial strain and cultural conditions.

Some enzymes and their applications have been discussed below

1. Lipase produced by Rhizopus sp., used in detergent formulations and helps in removing oily stains from the laundry due to its digestive application.
2. Pectinase produced by Aspergillus sp., used for clarifying bottled fruit juices.
3. Proteases They are produced by Aspergillus niger and Bacillus subtilis. They are used as clarifying agents for beer, meat tenderizer, etc.
4. Amylase produced by Aspergillus sp., used for digestive purpose and in the preparation of glucose syrup.
5. Cellulase produced by Trichoderma viridie, used for the degradation of cellulose.

Streptokinase produced by Streptococcus and modified by genetic engineering is used as a clot buster for removing clots from blood vessels of patients, who have undergone myocardial infarction leading to heart attack.

Production of Bioactive Molecules:
The bioactive molecules produced by microbes are

1. Cyclosporin-A It is produced by Trichoderma polysporum (fungus). It is used as an immunosuppressive agent for the patients, who have undergone organ transplantation.
2. Statins They are produced by Monascus purpureus (yeast) and are used as blood cholesterol lowering agents.

Question 2.
Explain how microbes are useful in pollution control and also in production of alternative source of energy.
Answer:
Microbes are major component of biological world on this earth. Although they are the causal agents of most of the infectious diseases, still they are of great importance to humans. Now, scientist are working on the ways in which with the use of microorganisms pollution problem can be solved. This can be done by bioremediation. In this technique microorganisms are used to neutralise pollutants from a contaminated site by their oxidation. Pollution can be controlled by microbes in two ways

1. By enhancing the growth and activity of microbes already present an pollutant site.
2. By adding some new microbes to the pollution site. Pollution control by the application of microbes works best when pollutants are a known mixture of organic compounds that are related to each other in structure and when there is no competition from indigenous microorganisms.

Production of Alternative Source of Energy :

Microbes in Biogas Production:
The excreta of cattle, commonly called gobar, is rich in methanogenic bacteria. Thus, cattle dung can be used for the generation of biogas, commonly called gobar gas. As cattle dung is available in large quantities in rural areas this method of biogas production is mostly functional in those areas.

Economically viable biogas is produced in large vessels called bioreactors.
Biogas plant consists of a concrete tank (10-15 feet deep) in which bio-wastes are collected and slurry of dung is fed. A floating cover is’placed over the slurry, which keeps on rising, as the gas is produced in the tank due to the microbial activity.

Methanobacterium present in the dung acts on the bio-waste to produce biogas. An outlet is also present which connects to a pipe that supplies biogas to the nearby houses.
Img 1

There is another outlet from which spent slurry is removed that can be used as fertiliser. Biogas production technology was developed in India mainly by Khadi and Village Industries Commission (KVIC) and Indian Agricultural Research Institute (LARI).

The production of biogas occurs in following three steps

Solubilisation: Decomposition of lipids, proteins, cellulose, hemicellulose, etc., present in organic matter to monomers by the action of hydrolytic enzymes like lipases, cellulases, proteases, peptidases, etc., secreted by microorganisms.

Acidogenesis: Conversion of monomers to organic acids with the help of fermentative microbes, e.g. Propionibacterium, Acetovibrio. The most common organic acid produced is acetic acid.

Methanogenesis: Biogas production with the action of methanogens, e.g. Methanococcus Methanobacillus.