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?

Practice Questions

Which process converts glucose into energy in the human body?

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Which gas is most abundant in Earth’s atmosphere?

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What type of electromagnetic radiation has the longest wavelength?

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What is the smallest unit of life?

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What type of energy is stored in a stretched rubber band?

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Which organ in the human body produces bile?

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Which law states that energy cannot be created or destroyed?

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What is the primary function of white blood cells?

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Which type of blood vessel carries blood away from the heart?

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What is the pH of pure water at 25°C?

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