Chapter 2
MICROORGANISMS : FRIEND AND FOE
1. Fill in the blanks.
(a) Microorganisms can be be seen with the help of a ________.
Ans-
(b) Blue green algae fix ______ directly from air to enhance fertility of soil.
Ans-
(c) Alcohol is produced with the help of _______.
Ans-
(d) Cholera is caused by ________.
Ans-
2. Tick the correct answer.
(a) Yeast is used in the production of
(i) sugar (ii) alcohol (iii) hydrochloric acid
(iv) oxygen
Ans-
(b) The following is an antibiotic
(i) Sodium (ii) Streptomycin (iii) Alcohol (iv) Yeast
Ans-
(c) Carrier of malaria-causing protozoan is
(i) female Anopheles mosquito (ii) cockroach
(iii) housefly (iv) butterfly
Ans-
(d) The most common carrier of communicable diseases is
(i) ant (ii) housefly (iii) growth of yeast cells
(iv) spider
Ans-
(e) The bread or idli dough rises because of
(i) heat (ii) grinding (iii) growth of yeast cells
(iv) kneading
Ans-
(f) The process of conversion of sugar into alcohol is called
Ans-
3. Match the organisms in Column A with their action in Column B.
A B
(i) Bacteria (a) Fixing nitrogen
(ii) Rhizobium (b) Setting of curd
(iii) Lactobacillus (c) Baking of bread
(iv) Yeast (d) Causing malaria
(v) A Protozoan (e) Causing Cholera
(vi) A virus (f) Causing AIDS
4. Can microorganisms be seen with the naked eye? If not. how can they be seen?
Ans-
5. What are the major groups of microorganisms?
Ans-
6. Name the microorganisms which can fix atmospheric nitrogen in the soil.
Ans-
7. Write 10 lines on the usefulness of microorganisms in our lives.
Ans-
8. Write a short paragraph on the harms caused by microorganisms.
Ans-
9. What are antibiotics? What precautions must be taken while taking antibiotics?
Ans-
Type- Ankur Moni Nath
