What are the major groups of microorganisms?

3

(a)

Write 10 lines on the usefulness of microorganisms in our lives.

3

(a)

Write a short paragraph on the harmful effects of microorganisms.

3

(a)

Microorganisms survive under adverse conditions. How?

3

(a)

What will happen to 'pooris' and 'unused kneaded flour' if they are left in the open for a day or two?

3

(a)

Classify the following into friendly and harmful microorganisms. Yeast, malarial parasite, Lactobacillus, bread mould, Rhizobium, Bacillus anthracis.

3

(a)

Yeast is very useful for baking industry. Elucidate the role of yeast.

3

(a)

Give an account of two important discoveries in the past that proved 'microorganisms can be useful to humans'.

3

(a)

Give some points to show that bacteria have beneficial effects.

3

(a)

Boojho wants to know what is pasteurization.

3

(a)

Why are salt and edible oils also called preservatives? Name two chemicals that are used as common preservatives.

3

(a)

Draw structure of virus and amoeba.

3

(a)

Explain the various shapes of bacteria.

3

(a)

How do vaccines work?

3

(a)

Shikha while teaching her sister about microbes explained that microbes are useful to humans. Hearing this, her sister Sneha got confused as she knew that her Uncle was suffering from TB caused by microbes. She asked this to Shikha. Shikha appreciated Sneha was asking this question and explained her.
(i) What are microbes?
(ii) How are microbes helpful to humans?
(iii) Mention two diseases other than TB caused by microbes.
(iv) Identify the values shown by Sneha.

3

(a)