Topic Details (Notes format)

Microorganisms: Friend and Foe

Subject: General Science

Book: NCERT Science Class 8

Microorganisms are tiny living organisms that cannot be seen with the naked eye. They include bacteria, viruses, fungi, and protozoa.
- **Useful Microorganisms**:
- Bacteria help in making curd and nitrogen fixation.
- Yeast is used in baking and fermentation.
- **Harmful Microorganisms**:
- Some bacteria and viruses cause diseases like tuberculosis and COVID-19.
- Fungi like bread mold spoil food.

**Possible Exam Questions:**
1. What are microorganisms? Classify them with examples.
2. How are bacteria useful in everyday life?
3. What are the harmful effects of microorganisms?
4. Discuss the role of vaccines in disease prevention.
5. How does yeast help in making bread and alcohol?