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Chapter Analysis
Intermediate14 pages • EnglishQuick Summary
The chapter 'Microorganisms : Friend and Foe' introduces microorganisms, their various types, and their characteristics. It covers the beneficial roles of microorganisms, such as their use in food production and medicine, as well as harmful effects like diseases in humans, plants, and animals. The chapter also discusses food preservation methods and the nitrogen cycle, highlighting how microorganisms contribute to environmental cleanliness and agricultural productivity.
Key Topics
- •Types of Microorganisms
- •Useful Microorganisms
- •Harmful Microorganisms
- •Food Preservation
- •Nitrogen Cycle
- •Antibiotics and Vaccines
- •Communicable Diseases
- •Environmental Impact of Microorganisms
Learning Objectives
- ✓Understand the classification of microorganisms.
- ✓Identify the roles of microorganisms in food production.
- ✓Analyze how microorganisms contribute to soil fertility and the environment.
- ✓Explain various methods of food preservation.
- ✓Describe the impact of harmful microorganisms on health.
- ✓Recognize the importance of antibiotics and their proper usage.
Questions in Chapter
Can microorganisms be seen with the naked eye? If not, how can they be seen?
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What are the major groups of microorganisms?
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Name the microorganisms which can fix atmospheric nitrogen in the soil.
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Write 10 lines on the usefulness of microorganisms in our lives.
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Write a short paragraph on the harmful effects of microorganisms.
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What are antibiotics? What precautions must be taken while taking antibiotics?
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Additional Practice Questions
Explain how microorganisms are used in the preparation of curd and bread.
mediumAnswer: Microorganisms like Lactobacillus are used in the preparation of curd. They multiply in milk and convert it into curd. Yeast is used in baking as it produces carbon dioxide which makes the dough rise.
Describe the role of microorganisms in the nitrogen cycle.
mediumAnswer: Microorganisms such as nitrogen-fixing bacteria convert atmospheric nitrogen into nitrates which plants can absorb. Decomposers break down organic matter, returning nitrogen to the soil.
What measures can be taken to prevent the spread of communicable diseases caused by microorganisms?
easyAnswer: Preventive measures include immunization, maintaining hygiene, using mosquito nets, consuming boiled water, and avoiding contact with infected persons.
How do food preservation methods prevent spoilage by microorganisms?
mediumAnswer: Food preservation methods, such as salting, sugaring, pasteurization, and airtight storage, inhibit the growth of spoilage-causing microorganisms by eliminating their favorable conditions.
What is the significance of antibiotics and what precautions should be taken when using them?
hardAnswer: Antibiotics are derived from microorganisms and treat bacterial infections. It's important to take them under a doctor’s guidance and complete the prescribed course to prevent antibiotic resistance.
NCERT Exemplar
AvailablePractice with NCERT Exemplar problems and solutions for this chapter. Exemplar problems are designed to help you master the concepts with advanced-level questions.
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