Nootan solutions for Biology [English] Class 12 ISC chapter 12 - Microbes in Human Welfare [Latest edition]

Which one of the following organisms does not have the ability to fix atmospheric nitrogen?

Inoculation of which one of the following free-living bacteria has been reported to increase the yield of rice?

Which one of the following plays an important role in phosphate nutrition of plants?

Itaconic acid is obtained on fermenting glucose solution by ______.

Roquefort cheese is ripened by the blue-mould ______.

Zymase enzyme is obtained from ______.

The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is ______.

Wastewater treatment generates a large quantity of sludge, which can be treated by ______.

Trichoderma, a free-living fungus can be used for ______.

Which one of the following is not a nitrogen-fixing organism?

Which one of the following alcoholic drinks is produced without distillation?

Methanogenic bacteria are not found in ______.

Big holes in Swiss cheese are made by ______.

Which fungus is used in alcohol industry?

The organisms which can bring about nutrient enrichment are called ______.

A symbiotic relationship between fungal hyphae and roots of higher plants is known as ______.

Saccharomyces ______ is commonly used to leaven the bread.

Ergot, prepared from a fungus, ______ is used to induce uterine contraction for abortions, menstrual disorders and to check haemorrhages.

State whether the following statement is true or false.

Ectomycorrhiza commonly occur on the roots of Pinus.

State whether the following statement is true or false.

Phosphorus is required for better nitrogen fixation by Rhizobium.

State whether the following statement is true or false.

Rhizobium is a free-living nitrogen-fixing bacterium.

State whether the following statement is true or false.

Biofertilizers are organisms which can bring about soil nutrient enrichment.

State whether the following statement is true or false.

Yeast cells are a very good source of vitamins B and D.

State whether the following statement is true or false.

Lactobacillus acidophilus is used to ferment milk.

State whether the following statement is true or false.

Gluconic acid is prepared by fermenting sugary solution by the species of Aspergillus.

State whether the following statement is true or false.

Gasohol is a mixture of gasoline and alcohol in equal ratio.

State whether the following statement is true or false.

Microbes play an important role in the treatment and cycling of sewage, organic and municipal wastes.

Give two examples of biofertilizer.

Mention the most significant function/role of Azotobacter.

What are biofertilizers?

Name four groups of organisms used as the main source of biofertilizers.

Elaborate the following:

VAM

Find out the name of the microbes from which cyclosporin A (an immunosuppressive drug) and statins (blood cholesterol lowering agents) are obtained.

Name any two species of fungus, which are used in the production of the antibiotics.

What is sewage?

Name the organism that causes large holes in ‘Swiss cheese’.

Why is Gambusia introduced into drains and ponds?

Give the scientific name of the source organism from which the first antibiotic was produced.

Name the nutrient that gets enhanced while curdling of milk by Lactobacillus.

List four advantages that a symbiotic mycorrhizal association provides to the host plant.

Why are the fruit juices bought from market clearer as compared to those made at home?

Name the metabolic pathway associated with the rising of dough in making bread. What makes the dough rise?

Name the gas released and the process responsible for puffing up of the bread dough when Saccharomyces cerevisiae is added to it.

How do ladybird beetles and dragonflies act as biocontrol agents?

Name the group of organisms and the substrate they act on to produce biogas.

Name a cyanobacterium that can fix atmospheric nitrogen.

Write the scientific name of the microbe used for fermenting malted cereals and fruit juices.

What makes the nucleopolyhedrovirus a desirable biological control agent?

How is presence of cyanobacteria in the paddy fields beneficial to rice crop?

Name a genus of fungi that forms a mycorrhizal association with plants.

Milk starts to coagulate when Lactic Acid Bacteria (LAB) is added to warm milk as a starter. Mention any two other benefits of LAB.

Mention a product of human welfare obtained with the help of the following microbe.

LAB

Mention a product of human welfare obtained with the help of the following microbe.

Saccharomyces cerevisiae

Mention a product for human welfare obtained with the help of the following microbe:

Propionibacterium shermanii

Mention a product for human welfare obtained with the help of the following microbe:

Aspergillus niger

State one reason for adding blue-green algae to the agricultural soil.

Mention two advantages of adding blue-green algae to paddy fields.

Name the enzyme produced by Streptococcus and its action (after being modified).

Name a microbe used for statin production.

How do statins lower blood cholesterol levels?

What are biofertilizers?

Name an immune immunosupressive agent?

What is mycorrhiza?

How has the bacterium Bacillus thuringiensis helped us in controlling caterpillars of insect pests?

Name a free-living and a symbiotic bacterium that serve as biofertilizer. Why are they so called?

What is Integrated Pest Management?

Given below is a list of six micro-organisms. State their usefulness to humans.

1. Nucleopolyhedrovirus
2. Saccharomyces cerevisiae
3. Monascus purpureus
4. Trichoderma polysporum
5. Penicillium notatum
6. Propionibacterium sharmanii

Write the full form of IPM.

Mention the most significant function/role of Azotobacter.

Mention the contribution of Alexander Fleming in the field of medicine.

Write the names of two bacteria which convert lactose sugar of milk into lactic acid.

Give the binomials of two types of yeast and the commercial bioactive products they help to produce.

Write the binomials of two fungi and mention the products/bioactive molecules they help to produce.

Name the microbe that helps in the production of the following product commercially:

Statin

Name the microbe that helps in the production of the following product commercially:

Citric acid

Name the microbe that helps in the production of the following product commercially:

Penicillin

Name the microbe that helps in the production of the following product commercially:

Butyric acid

How does the application of the fungal genus, Glomus, to the agricultural farm increase the farm output? 

Give the biological name of the following:

The mould from which penicillin is obtained.

Give the biological name of the following:

Baker’s yeast

Give the biological name of the following:

The microbe used to control insect larvae growing on cotton.

Give the biological name of the following: 

The microbe used to produce Swiss cheese.

Give the biological name of the following:

The fungus that is being developed as a bio-control agent.

Give the biological name of the following:

A symbiotic nitrogen-fixing bacterium found in root nodules.

What makes cyanobacteria agriculturally important?

What are biofertilizers?

What are biofertilizers main sources? 

What is biological nitrogen fixation?

Name two organisms which fix nitrogen asymbiotically.

Name two organisms which fix nitrogen symbiotically.

Write a short note on mycorrhiza.

Write a short note on Role of VAM in crop improvement.

Write short notes on rhizobium-legume symbiosis.

Define Biofertilizer.

How does the following serve as a biofertilizer?

Ectomycorrhizae

How does the following serve as a biofertilizer?

Rhizobium

How does the following serve as a biofertilizer?

Azospirillum

Why are bio-fertilizers preferred over chemical fertilizers?

Why are the spores of Bacillus thuringiensis used as bioinsecticide?

A patient brought to a hospital with myocardial infarction is immediately administered ______.

Which of the following is NOT used as a biocontrol agent for plant diseases?

Which of the following is used for the production of ethanol from starch at the industrial level?

______ is a mutual association of fungal hyphae with the roots of higher plants.

Match column I with column II and select the correct option from the choices given below: 

Matching codes:

Choose the odd one among the following with reference to microbes as biofertilizers:

1. Ladybird beetles 
2. Azotobacter 
3. Azospirillum 
4. Rhizobium

Study the diagram given below and answer the question that follow:

1. Sewage is defined as:
   1. Municipal solid waste. 
   2. Municipal waste water. 
   3. Non-biodegradable waste. 
   4. Biodegradable plastic waste.
2. The primary treatment of waste involves:
   1. mechanical removal of grit. 
   2. chlorination 
   3. addition of microbes. 
   4. removal of harmful colours.
3. As a part of secondary treatment floes are added. What are these floes?
   1. Masses of specific chemicals to treat the waste. 
   2. Pieces of spongy material to absorb the waste. 
   3. Masses of bacteria associated with fungal filaments.
   4. Biodegradable masses trapped in mesh-like structures.
4. What is the effect of the process of sewage treatment on the value of the BOD?
   1. Increases
   2. Decreases
   3. Remains unaffected
   4. becomes unstable
5. A major part of the studge is pumped into large sludge digester tanks where a mixture of gases is produced. The main component of this gaseous mixture is:
   1. Carbon dioxide 
   2. Hydrogen 
   3. Hydrogen sulphide 
   4. Methane

The leaves of Azolla are used as biofertilizer. Comment upon the statement. 

Name the blank spaces a, b, c and d in the table given below:

Identify a, b, c, d, e and f in the table given below:

Explain the significant role of the genus Nucleopolyhedrovirus in an ecological sensitive area.

Name the genus to which baculoviruses belong. Describe their role in integrated pest management programmes.

Name a genus of baculovirus.

Why are baculoviruses considered good biocontrol agents?

How do organic farmers control pests?

Give two examples of how organic farmers control pests.

State the difference in organic farmers approach from that of conventional pest control methods.

Study the table given below, and write the answers in the correct order.

Organic farmers prefer biological control of diseases and pests to the use of chemicals for the same purpose. Justify.

Give an example of a bacterium, a fungus and an insect that are used as biocontrol agents.

Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes with the help of a microscope, which sample would you carry and why?

Give examples to prove that microbes release gases during metabolism.

In which food would you find lactic acid bacteria? Mention some of their useful applications.

Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve use of microbes.

In which way have microbes played a major role in controlling diseases caused by harmful bacteria?

Name any two species of fungus, which are used in the production of the antibiotics.

What is sewage?

In which way can sewage be harmful to us?

What is the key difference between primary and secondary sewage treatment?

Do you think microbes can also be used as a source of energy? If yes, how?

Microbes can be used to decrease the use of chemical fertilisers and pesticides. Explain how this can be accomplished.

Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20 mg/L, 8 mg/L and 400 mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each, assuming the river water is relatively clean?

Find out the name of the microbes from which cyclosporin A (an immunosuppressive drug) and statins (blood cholesterol lowering agents) are obtained.

Find out the role of microbes in the following:

Single cell protein (SCP)

Find out the role of microbes in the following:

Soil

Arrange the following in the decreasing order (most important first) of their importance for the welfare of human society. Give reasons for your answer.

Biogas, Citric acid, Penicillin and Curd

How do biofertilisers enrich the fertility of the soil?

Choose any three microbes, from the following which are suited for organic farming which is in great demand these days for various reasons. Mention one application of each one chosen.

Mycorrhiza, Monascus, Anabaena, Rhizobium, Methanobacterium, Trichoderma.

Prakash mother is suffering from high blood pressure. He took her to a cardiologist. He advised her for several blood tests, including lipid profile. Prakash found high cholesterol level in her blood. On hearing, she was much puzzled. Doctor prescribed some medicines to control high blood pressure and cholesterol level in the blood. In your opinion, what doctor has prescribed her to lower cholesterol level. How the medicine works?

Protein is an important constituent of our food. Malnutrition caused by an inadequate dietary intake of protein leads to stunting, wasting and kwashiorkor. In a vegetarian society, pulses are the main source of protein. However a large population of developing countries earl not afford pulses. On one day, I read in newspaper that several microorganisms are good source of proteins and can be used commercially as food supplement. The proteins obtained by microbes is referred as ‘single cell protein’ (SCP). As a biology student, then you asked your teacher, what are ‘SCP’ and the important sources of SCP and how large scale production of microbial biomass is advantageous as compared with traditional methods of producing proteins for food or feed?

Modern agriculture rely heavily on a wide range of synthetic chemicals which include different types of fertilizers and pesticides. Use of these chemicals has played a very vital role in increased agricu ltural production. However, use of chemical fertil izers is a costly input and their manufacture depends on the dwindl ing resources of energy such as petroleum and coal. Moreover, chemical fertilizers being industrial products are subjected to cost increases every year and becoming unaffordable to a large segment of farmers. As an agricultural scientist, can you suggest some cheap and eco-friendly method to boost agricultural production.

Your advice is sought to improve the nitrogen content of the soil to be used for cultivation of a non-leguminous terrestrial crop.

1. Recommend two microbes that can enrich the soil with nitrogen.
2. Why do leguminous crops not require such enrichment of the soil?