Microorganisms: Friend & Foe

Q.1: Microorganisms are classified into ____ groups.

a) 5

b) 4

c) 2

Q.2: All microorganisms are single-celled.

a) True

b) False

Q.3: ___________ bacterium promotes the formation of curd.

a) Rhizobium

b) Lactobacillius

c) Yeast

Q.4: Microorganism like _________ only reproduce inside the cells of the host organism.

a) Virus

b) Fungi

c) Bacteria

Q.5: Which of the following disease is caused by protozoa ?

a) malaria

b) typhoid

c) polio

Q.6: Which of the following microorganism lives in colonies ?

a) bacteria

b) fungi

c) both

Q.7: The process of conversion of sugar into alcohol by adding yeast is called ______________.

a) pasteurisation

b) sedimentation

c) fermentation

Q.8: __________________ discovered the vaccine for small pox in 1798.

a) Edward Jenner

b) Louis Pateur

c) Alexander Fleming

Q.9: Yeast reproduces rapidly and produces __________ gas during respiration.

a) carbon dioxide

b) oxygen

c) hydrogen

Q.10: The medicines which kill or stop the growth of disease causing microbes are called ____________.

a) Vaccines

b) Antibiotics

c) None

Q.11: Some microbes can fix the nitrogen from the atmosphere to enrich the soil’s fertility. They are known as ____________________.

a) Biological nitrogen fixers

b) Nitrogen spreaders

c) Nitrogen producers

Q.12: Microbial diseases that can spread from an infected person to a healthy person through water, air, food or physical contact, are known as ___________ diseases.

a) communicable

b) non-communicable

c) none

Q.13: Why antibiotics are not effective against cold and flu ?

a) Because these are caused by bacteria.

b) Because these are caused by protozoa.

c) Because these are caused by virus.

Q.14: When a disease carrying microbe enters our body, the body produces _________ to fight the invader.

a) antibodies

b) antigens

c) none

Q.15: __________ mosquito carries the parasite of malaria.

a) Aedes

b) Anopheles

c) Both

Q.16: Disease causing microbes are called ___________.

a) harmless

b) pathogen

c) non-pathogen

Q.17: In pasteurization method, the milk is heated at ______ o C for 15 to 30 seconds and then suddenly cooled down.

a) 40

b) 90

c) 70

Q.18: _______________ discovered the Bacillus anthracis which causes anthrax disease.

a) Alexander Fleming

b) Robert Koch

c) Edward Jenner

Q.19: Which of these things you have to keep in mind while taking antibiotics ?

i) It should be prescribed by a qualified doctor.

ii) It should be costly.

iii) The patient should complete the course of antibiotics prescribed by the doctor.

a) Only iii

b) i and ii

c) i and iii

Q.20: Yeast can be grown on natural sugars present in grains like _____________.

a) wheat and barley

b) rice and wheat

c) both


  1. b
  2. b
  3. b
  4. a
  5. a
  6. c
  7. c
  8. a
  9. a
  10. b
  11. a
  12. a
  13. c
  14. a
  15. b
  16. b
  17. c
  18. b
  19. c
  20. c

Published by Priya Prakash

In the midst of winter, i found there was within me an invincible summer ~ Albert Camus

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