Home/
Notes/
Class 8/
Science/
Microorganisms: Friend and Foe/
Practice

Microorganisms: Friend and Foe Practice

Solve chapter-level practice questions for Microorganisms: Friend and Foe with reveal-only solutions and quick revision support.

Practice Set 1 — Groups and Useful Roles

Types of microbes, fermentation, medicines, and soil fertility.

Attempted 0/5
Correct 0

Self-checked progress is stored in this browser, not synced to an account.

Q1.
Name the four major groups of microorganisms and give one example of each.
Q2.
Which microorganism is used to make curd, and which to make bread?
Q3.
What are antibiotics? Name one and state one precaution in using them.
Q4.
How do Rhizobium bacteria increase soil fertility?
Q5.
What is a vaccine and how does it protect us?

Practice Set 2 — Harmful Microbes and Preservation

Pathogens, carriers, food spoilage, and methods of preservation.

Attempted 0/5
Correct 0

Self-checked progress is stored in this browser, not synced to an account.

Q1.
What are pathogens? Give one disease each caused by a bacterium, a protozoan, and a virus.
Q2.
Name the microbe and the carrier for malaria and for dengue.
Q3.
How do salt and sugar help preserve food?
Q4.
What is pasteurisation?
Q5.
Give two chemical preservatives commonly added to jams and squashes.

Quick Q&A Before You Revise

Are all microorganisms harmful?

No. Many are extremely useful — they make curd and bread, produce antibiotics and alcohol, decompose waste, and fix nitrogen in the soil. Only some are pathogens.

Why don't antibiotics work against the common cold?

The common cold is caused by a virus, and antibiotics act only on bacteria and fungi. Viral infections are prevented by vaccines and are usually managed by rest and symptomatic treatment.

Why does food kept in a refrigerator last longer?

Low temperature slows down the growth and reproduction of the microorganisms that spoil food, so spoilage is delayed (though not stopped completely).

Struggling with Microorganisms: Friend and Foe?
Book a free 1:1 demo with a Science tutor and get chapter-wise help that matches your pace.
Book a Free Demo