NCERT Solutions Class 8 Science Chapter 2 - Microorganisms Friend and Foe

Our NCERT Solutions for Chapter 2, "Microorganisms: Friend and Foe," provide detailed explanations and answers to all the questions in the textbook. They help students comprehend microorganisms, including their characteristics and classification based on structure and function. Furthermore, these solutions lay a strong foundation for future learning by discussing the detrimental effects of microorganisms, including diseases brought on by bacteria, viruses, protozoa, and fungi.

Students looking to score well in their Class 8 Science exams need to practice regularly to understand the exam pattern and build confidence. The NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe include all key questions based on the latest syllabus, making them a valuable resource. You can also download the free PDF of Class 8 Science Chapter 2 to explore these concepts in depth and improve your academic performance.

1.0Science Chapter 2 Microorganisms: Friend and Foe Class 8 PDF

The Microorganisms: Friend and Foe Class 8 PDF can be downloaded, which will give you a thorough understanding of the curriculum's key concepts. These resources are extremely beneficial for students studying the first chapter of Science.

2.0NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe Overview

Here is a brief overview of the class 8 science chapter that will make you understand what we have covered:

• Explains what microorganisms are, their features, and their classification based on structure and function.
• Describes how microorganisms benefit agriculture, medicine, and food production.
• This section discusses the harmful impacts of microorganisms, such as diseases caused by bacteria, viruses, protozoa, and fungi.
• Highlights how microorganisms help decompose waste and recycle nutrients, maintaining environmental balance.
• Provides questions and answers to help students assess their understanding and readiness on the topic.
• This section follows the latest 2024-25 syllabus, with supporting resources such as notes, key concepts, and examples.

3.0Subtopic of Class 8 Science Chapter 2 Microorganisms: Friend and Foe

The key topics explored in CBSE Class 8 Science Chapter 2 provide a comprehensive overview of the essential concepts covered in this chapter.

• Microorganisms
• Where do Microorganisms Live?
• Microorganisms and Us
• Food Preservation
• Nitrogen Fixation
• Nitrogen cycle

4.0NCERT Solutions Class 8 Science Chapter 2 - Detailed Solutions

A single exercise contains 9 questions, all of which are fill-in-the-blanks and descriptive types. You can check all the questions for practice from the PDF below. You can access it easily and strengthen your preparation.

• Fill in the blanks: (i) Microorganisms can be seen with the help of a _. (ii) Blue green algae fix directly from air to enhance fertility of soil. (iii) Alcohol is produced with the help of . (iv) Cholera is caused by . Ans. (i) microscope (ii) nitrogen (iii) yeast (iv) bacteria
• Tick the correct answer - (a) Yeast is used in the production of - (i) Sugar (ii) Alcohol (iii) Hydrochloric acid (iv) Oxygen (b) The following is an antibiotic (i) Sodium bicarbonate (ii) Streptomycin (iii) Alcohol (iv) Yeast (c) Carrier of malaria causing protozoan is - (i) Female Anopheles mosquito (ii) Cockroach (iii) Housefly (iv) Butterfly (d) The most common carrier of communicable diseases is - (i) Ant (ii) Housefly (iii) Dragonfly (iv) Spider (e) The bread or idli dough rises because of - (i) Heat (ii) Grinding (iii) Growth of yeast cells (iv) Kneading (f) The process of conversion of sugar into alcohol is called (i) Nitrogen fixation (ii) Moulding (iii) Fermentation (iv) Infection Ans. (a) ii (b) ii (c) i (d) ii (e) iii (f) iii
• Match the organisms in column-A with their actions in column-B

Ans. (1) e (2) a (3) b (4) c (5) d (6) f.

• Can microorganisms be seen with the naked eye? If not, how can they be seen? Ans. No, microorganisms cannot be seen with naked eyes. They are so small that they cannot be seen with naked eyes. A microscope is required to see these organisms.
• What are the major groups of microorganisms? Ans. Microorganisms are mainly divided into five groups: Bacteria, Fungi, Protozoa, Algae and Virus.
• Name the microorganisms which can fix atmospheric nitrogen in the soil. Ans. Certain type of bacteria and blue green algae fix atmospheric nitrogen. For example, Bacteria like Rhizobium, Azotobacter and blue green algae likeAnabaena, Nostoc.
• Write ten lines on the usefulness of microorganisms in our lives. Ans. Microorganisms are very useful to us. Some of their usefulness is as follows: (i) They are used in the preparation of curd, bread and cake. Lactobacillus promotes the formation of curd. (ii) Yeast is used for commercial production of alcohol and wine while Acetobacter bacteria cause conversion of alcohol to vinegar. (iii) In medical industry antibiotics are made from microorganisms like - some fungi and bacteria. (iv) Microorganisms are also used to prepare vaccines for various diseases. (v) Microorganisms (bacteria) help us in cleaning of our environment as they decompose the dead bodies of plants and animals and other organic wastes. (vi) In agriculture, microorganisms are used to increase soil fertility by fixing nitrogen. Some bacteria like - Rhizobium and some blue green algae are able to fix nitrogen from the atmosphere to enrich soil and thus increase its fertility. (vii) It is due to the activities of microorganisms because of which we are able to prepare manure by decomposing organic wastes and dead bodies of plants and animals. (viii) In food industry, they are used as preservatives for food items. (ix) Some fungi are eaten raw as food such as, Mushrooms. (x) Yeast is used in the baking industry.
• Write a short paragraph on the harmful effect of microorganisms. Ans. Microorganisms can be very harmful to us, as they cause a number of human and animal diseases. Diseases in humans like the common cold, tuberculosis, measles, chicken pox, polio, cholera, typhoid, hepatitis-B, malaria etc. are caused by microorganisms. Some serious diseases like Anthrax are a dangerous human and cattle disease caused by bacteria. Microbes grow on food products and render them unfit for consumption. Consumption of such food causes food poisoning. Microbes also spoil clothes and leather products. Microorganisms cause diseases of plants like-blights in potatoes, sugarcanes, oranges, rust of wheat, citrus canker etc. They also reduce the crop yield.
• What are antibiotics? What precautions must be taken while taking antibiotics? Ans. Medicines taken to kill or stop the growth of harmful or disease-causing microbes in human body are called antibiotics. Antibiotics are very useful as only antibiotics can save us from many microbial infections and diseases. They are made from fungi and bacteria. Alexander Fleming discovered the first antibiotic called Penicillin in 1929. Now-a-days a number of antibiotics are used to cure a variety of human, animal and plant diseases. Streptomycin, Erythromycin, Tetracycline etc are some commonly used antibiotics. Precautions for taking antibiotics: Antibiotics should only be taken when advised by a qualified physician. Moreover, it should only be taken when needed otherwise; they become less effective for future use. Also, antibiotics taken unnecessarily may kill the beneficial bacteria in the body.

5.0Benefits of NCERT Science Class 8 Solutions: Chapter 2

You should opt for the NCERT solution for Class 8 Science Chapter 2 for some reasons. These will help you to understand the importance of a solution:

• The NCERT Solution class 8 science chapter 2 covers essential concepts like farming techniques, soil preparation, planting and irrigation, and building a solid foundation.
• The solutions are neatly organized, making it easy for students to find and review information.
• Offers clear explanations for solving problems and understanding complex agricultural topics.
• Contains exercises to help students test their understanding and reinforce what they’ve learned.
• Provides thorough coverage of all key topics, helping students confidently prepare for exams.