Biology

Microbes in Human Welfare

Question:

Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of waste waters rich in organic matter? Discuss.

Answer:

Secondary treatment or Biological treatment: The primary effluent is passed into large aeration tanks where it is constantly agitated mechanically and air is pumped into it. This allows vigorous growth of useful aerobic microbes into floes (masses of bacteria associated with fungal filaments to form mesh like structures). While growing, these microbes consume the major part of the organic matter in the effluent. This significantly reduces the BOD (biochemical oxygen demand) of the effluent. BOD refers to the amount of the oxygen that would be consumed if all the organic matter in one litre of water were oxidised by bacteria. The sewage water is treated till the BOD is reduced. The BOD test measures the rate of uptake of oxygen by micro ¬organisms in a sample of water and thus, indirectly, BOD is a measure of the organic matter present in the water. The greater the BOD of waste water, more is its polluting potential.
Once the BOD of sewage or waste water is reduced significantly, the effluent is then passed into a settling tank where the bacterial ‘floes' are allowed to sediment. This sediment is called activated sludge. A small part of the activated sludge is pumped back into the aeration tank to serve as the inoculum. The remaining major part of the sludge is pumped into large tanks called anaerobic sludge digesters. Here, other kinds of bacteria, which grow anaerobically, digest the bacteria and the fungi in the sludge. During this digestion, bacteria produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide. These gases form biogas and can be used as source of energy as it is inflammable.

previuos
next

Microbes in Human Welfare

Q 1.

Name the states involved in Ganga action plan.

Q 2.

What is a broad spectrum antibiotic? Name one such antibiotic.

Q 3.

How do biofertilizers enrich the fertility of the soil?

Q 4.

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

Q 5.

Give an example of a rod shaped virus.

Q 6.

Name a microbe used for statin production. How do statins lower blood cholesterol level?

Q 7.

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

Q 8.

Find out the role of microbes in the following and discuss it with your teacher.
(a) Single cell protein (SCP)
(b) Soil

Q 9.

Name the scientists who were credited for showing the role of Penicillin as an antibiotic.

Q 10.

How do microbes reduce the environmental degradation caused by chemicals?

Q 11.

What is sewage? In which way can sewage be harmful to us?

Q 12.

Name an immune immunosuppressive agent.

Q 13.

What for Nucleopolyhydro viruses are being used now-a-days?

Q 14.

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

Q 15.

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

Q 16.

Give any two microbes that are useful in biotechnology.

Q 17.

What is the group of bacteria found in both the rumen of cattle and sludge of sewage treatment?

Q 18.

Which type of food would have lactic acid bacteria? Discuss their useful application.

Q 19.

(a) Discuss about the major programs that the Ministry of Environment and Forests, Government of India, has initiated for saving major Indian rivers from pollution.
(b) Ganga has recently been declared the national river. Discuss the implication with respect to pollution of this river.

Q 20.

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

Q 21.

What are biofertilisers? Give two examples.

Q 22.

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

Q 23.

Give examples to prove that microbes release gases during metabolism.

Q 24.

What is the source organism for EcoRI, restriction endonuclease?

Q 25.

Name any two industrially important enzymes.

Q 26.

How do mycorrhizal fungi help the plants harbouring them?

Q 27.

How has the discovery of antibiotics helped mankind in the field of medicine?

Q 28.

Which species of Penicillium produces Roquefort cheese?

Q 29.

(a) What would happen if a large volume of untreated sewage is discharged into a river?
(b) In what way anaerobic sludge digestion is important in sewage treatments?

Q 30.

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 under a microscope, which sample would you carry and why?

Q 31.

Write the most important characteristic that Aspergillus niger, Clostridium butylicum and Lactobacillus share.

Q 32.

What would happen if our intestine harbours microbial flora exactly similar to that found in the rumen of cattle?

Q 33.

Why are cyanobacteria considered useful in paddy fields?

Q 34.

Name a microbe used for the production of Swiss cheese.

Q 35.

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

Q 36.

What roles do enzymes play in detergents that we use for washing clothes? Are these enzymes produced from some unique microorganisms?

Q 37.

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

Q 38.

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/Land 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?

Q 39.

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

Q 40.

What are fermentors?

Q 41.

Why do we prefer to call secondary waste water treatment as biological treatment? .

Q 42.

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.

Q 43.

What is the chemical nature of biogas? Name an organism which is involved in biogas production.

Q 44.

Why are floes important in biological treatment of waste water?

Q 45.

How do bioactive molecules of fungal origin help in restoring good health of humans?

Q 46.

Which bacterium has been used as a clot buster? What is its mode of action?

Q 47.

How was penicillin discovered?

Q 48.

Why does Swiss cheese' have big holes?

Q 49.

Why is distillation required for producing certain alcoholic drinks?

Q 50.

Why are blue green algae not popular as biofertilisers?