Q4 of 9 Page 29

Can microorganisms be seen with the naked eye? If not, how can they be seen?

Micro-organisms are too much smaller that they cannot be seen with naked eye. They can be seen with a magnifying glass called microscope. For example, fungus that grows on bread is so small that it can be seen only with the help of a magnifying glass or microscope.


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2

Tick the correct Solution:

(a) Yeast is used in the production of


(i) sugar (ii) alcohol (iii) hydrochloric acid (iv) oxygen


(b) The following is an antibiotic


(i) Sodium bicarbonate (ii) Streptomycin (iii) Alcohol (iv) Yeast


(c) Carrier of malaria-causing protozoan is


(i) female Anopheles mosquito (ii) cockroach (iii) housefly (iv) butterfly


(d) The most common carrier of communicable diseases is


(i) ant (ii) housefly (iii) dragonfly (iv) spider


(e) The bread or idli dough rises because of


(i) heat (ii) grinding (iii) growth of yeast cells (iv) kneading


(f) The process of conversion of sugar into alcohol is called


(i) nitrogen fixation (ii) moulding (iii) fermentation (iv) infection

 3

Match the organisms in Column I with their action in Column II.

 5

What are the major groups of microorganisms?

 6

Name the microorganisms which can fix atmospheric nitrogen in the soil.