CBSE (Science) Class 12CBSE
It's free!


Create free account

      Forgot password?

View all notifications
Books Shortlist
Your shortlist is empty

NCERT solutions Biology Class 12 chapter 10 Microbes in Human Welfare


NCERT Biology Class 12

Biology Textbook for Class 12

Chapter 10 - Microbes in Human Welfare

Pages 189 - 190

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 1 | Page 189

Give examples to prove that microbes release gases during metabolism.

Q 2 | Page 189

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

Q 3 | Page 189

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

Q 4 | Page 189

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

Q 5 | Page 189

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

Q 6 | Page 189

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

Q 7 | Page 189

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

Q 8 | Page 189

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

Q 9 | Page 189

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

Q 10 | Page 189

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 20mg/L, 8mg/L and 400mg/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 11 | Page 189

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

Q 12 | Page 190

Find out the role of microbes in the following

Single cell protein (SCP)

Q 13.1 | Page 190

Find out the role of microbes in the following 


Q 13.2 | Page 190

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 14 | Page 190

How do biofertilisers enrich the fertility of the soil?

Q 15 | Page 190

NCERT Biology Class 12

Biology Textbook for Class 12