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Important questions Class VIII Science Chapter 2 Microorganisms - Friend and Foe




Fill in the blanks:

1. ___________ bacteria causes citrus canker.
2. ___________ is a skin disease in human caused by fungus.
3. The female Aedes mosquito is a carrier of the ________virus.
4. _______, ______ are chemicals that inhibit microbial growth.
5. When an antigen enters the body, the body produce proteins called ________ to destroy it.
6. A _________ is used to study microbes.
7. ________ is a unicellular fungus.
8. ________ made the first vaccine.
9. ________ microbe is present in our intestine as a friendly microbes.
10. ________ can kill disease causing microbes without causing injury to body.
11. _________ are on the borderline of living and non- living.
12. _______and ______ are two diseases caused by bacteria.
13. In legumes, the root nodules contain the bacterium_________.
14. Yeast is added to dough to produce _________which makes the dough rise.
15. The heating of milk upto to 70*C& then suddenly cooling is called _________.

SHORT QUESTIONS

Question 1.
Name two parasitic protozoa that cause diseases in human?

Question 2.
What are antibiotics?

Question 3.
What is fermentation?

Question 4.
What is pasteurization? How is it useful?

Question 5.
What are vaccines? How does a vaccine work?

Question 6.
Which microorganism acts as decomposers? How is this activity useful to us?

Question 7.
Describe the role of Rhizobium in maintaining soil fertility?

Question 8.
What is communicable disease?

Question 9.
Microbes will never grow food keep inside refrigerator? Do you agree why?

Question 10.
Define- Food preservation and Food poisoning


Practice Questions:

1. What is pathogen? How does it gain entry into the body of living organisms?
2. Why are bacteria and fungi said to be decomposers?
3. Give two ways in which bacteria are useful to us and two ways in which they are harmful?
4. Discuss five methods of food preservation?
5. Explain how microbes are useful to us?
6. Why are viruses considered to be the borderline between living and the non- living?
7. How do viruses cause diseases?
8. What is nitrogen cycle?
9. Which microorganism is used to make bread soft and fluffy? Discuss how this happens?
10. How does mosquito help in spreading microorganism?


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