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

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NCERT Class 8 Science Chapter 2 Microorganisms: Friend and Foe

If there’s one subject where learning is endless, it’s science. No matter how much time you spend reviewing theories, definitions, or diagrams, you might still feel there’s more to grasp. That’s why, when studying science, it’s essential not to skip answering questions—they help you truly understand and retain what you’ve learned.

For students looking to test their knowledge, answering questions in science is a great way to see how much they’ve retained. INFINITY LEARN provides detailed, solved NCERT solutions, including Class 8 Science Chapter 2 Question Answer, to help students review and reinforce their understanding. If you’re seeking NCERT solutions of class 8 for other chapters or want to strengthen your science knowledge, INFINITY LEARN also offers comprehensive Class 8 Science NCERT Solutions for all chapters, perfect for exam preparation.

Class 8 Science Chapter 2 Question Answer PDF

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MICROORGANISMS FRIEND AND FOE

Class 8 Science chapter 2 Question Answer

Here are all the science Class 8 chapter 2 question answer from the NCERT textbook.

1. Fill in the blanks :

Microorganisms can be seen with the help of a __________.
Blue green algae fix __________ directly from air to enhance fertility of soil.
Alcohol is produced with the help of __________.
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 (P) iii) hydrochloric acid iv) oxygen

b. The following is an antibiotic :

i) Sodium bicarbonate ii) Streptomycin (P) iii) Alcohol iv) Yeast

c. Carrier of malaria-causing protozoan is :

i) female Anopheles mosquito (P) ii) cockroach iii) housefly iv)butterfly

d. The most common carrier of communicable diseases is :

i) ant ii) housefly (P) iii) dragonfly iv) spider

e. The bread or idli dough rises because of :

i) heat ii) grinding iii) growth of yeast cells (P) iv) kneading

f. The process of conversion of sugar into alcohol is called :

i) nitrogen fixation ii) moulding iii) fermentation (P) iv) infection

CBSE Class 8 Science Syllabus 2024-25

3. Match the organisms in Column A with their action in Column B.

Column A Column B

i) Bacteria ( ) a) Fixing nitrogen

ii) Rhizobium ( ) b) Setting of curd

iii) Lactobacillus ( ) c) Baking of bread

iv) Yeast ( ) d) Causing malaria

v) A protozoan ( ) e) Causing cholera

vi) A virus ( ) f) Causing AIDS

g) Producing antibodies

Ans. i) e ii) a iii) b iv) c v) d vi) f

4. Can microorganisms be seen with the naked eye ? If not, how can they be seen ?

Ans. i) Microorganisms cannot be seen with the naked eye.

ii) They can be seen with the help of a magnifying glass or microscope.

5. What are the major groups of microorganisms ?

Ans. Microorganisms are classified into four major groups. They are –

i) Bacteria ii) Fungi iii) Protozoa v) Algae

6. Name the microorganisms which can fix atmospheric nitrogen in the soil.

Ans. Rhizobium, Anabaena, Nostoc, Azotobacter, etc.

7. Write 10 lines on the usefulness of microorganisms in our lives.

Ans. i) Microorganisms play an important role in our lives.

ii) Microorganisms are used for various purposes such as bread making, preparation of curd, alcoholic beverages, vinegar etc.

iii) Some of the bacteria are used in the preparation of medicines.

iv) They play an important role in the decomposition of organic wastes and keeping the environment clean.

v) Some microorganisms increase the fertility of the soil by fixing nitrogen.

vi) Microorganisms are used for the production of vaccines.

vii) Certain microorganisms are used in the biological treatment of sewage.

viii) They are also used for the production of antibiotics.

NCERT Exemplar Class 8 Science Solutions – Free PDF Download

8. Write a short paragraph on the harms caused by microorganisms.

Ans. i) Microorganisms cause diseases in animals. Eg : In cattle, the foot and mouth disease is caused by a virus.

ii) Several microbes cause diseases in plants. Eg : The productivity of wheat, orange, apple etc. is reduced due to microbial diseases in plants.

iii) Certain microbes, on entering into our body, produce toxic substances. This leads to diseases.

iv) Some microorganisms such as fungus spoil our food. For example, bread when left unused under moist conditions gets spoilt by fungus.

v) Some of the protozoans cause serious diseases like dysentery and malaria.

9. What are antibiotics? What precautions must be taken while taking antibiotics?

Ans. The medicines produced by certain microorganisms used to kill other disease-causing micro-organisms are called antibiotics. (or) The chemical substances that kill or stop the growth of microorganisms are called antibodies.

Eg : Streptomycin, tetracycline, penicillin etc.

Precautions to be taken while using antibiotics:

Antibiotics should be taken under the supervision of a well qualified doctor.
Course (intake) of antibiotics should be completed as per the prescription given by the doctor.
Antibiotics should be taken in the right amount and at the right time.

NCERT Solutions for Class 8 Science Chapter 2 – Short Questions with answers

Here are all the short type class 8 science chapter 2 question answer:

Question 1: What are microorganisms?

Answer: Microorganisms are tiny living things that can only be seen with a microscope. They include bacteria, viruses, fungi, protozoa, and algae.

Question 2: Name some common diseases caused by microorganisms.

Answer: Some common diseases caused by microorganisms are:

Bacteria: Tuberculosis, Cholera
Viruses: Common cold, Influenza, AIDS
Fungi: Athlete’s foot, Ringworm
Protozoa: Malaria, Amoebiasis

Question 3: How do microorganisms help in making curd and bread?

Answer: Microorganisms like bacteria help in making curd by converting milk into curd. Yeast, a type of fungus, helps in making bread by producing carbon dioxide, which makes the dough rise.

Question 4: What role do microorganisms play in cleaning the environment?

Answer: Microorganisms help in decomposing dead plants and animals. This process recycles nutrients back into the soil, cleaning the environment and enriching the soil.

Question 5: How can microorganisms be harmful?

Answer: Microorganisms can cause diseases in humans, animals, and plants. They can also spoil food, making it unsafe to eat.

Question 6: What are antibiotics? Give an example.

Answer: Antibiotics are medicines that kill or stop the growth of harmful microorganisms. An example of an antibiotic is penicillin.

Question 7: What is fermentation? Name a product made by this process.

Answer: Fermentation is a process where microorganisms convert sugars into alcohol or acids. An example of a product made by fermentation is yogurt.

Question 8: How can we preserve food from spoilage by microorganisms?

Answer: We can preserve food by methods such as refrigeration, canning, drying, salting, and adding preservatives. These methods slow down or stop the growth of microorganisms.

Question 9: Why is it important to take a full course of antibiotics?

Answer: It is important to take a full course of antibiotics to make sure all the harmful microorganisms are killed. If the course is not completed, some microorganisms may survive and become resistant to the antibiotic.

Question 10: How do vaccines work?

Answer: Vaccines work by stimulating the body’s immune system to recognize and fight specific microorganisms. They contain weakened or dead microorganisms that prepare the immune system to defend against future infections.

NCERT Solutions Class 8 Science Chapter 2

Many students find science to be a difficult subject. To avoid this circumstance, students should begin brushing up on their understanding of this subject months in advance. A pupil should ideally read the full NCERT book. It is also necessary to learn and practice questions on a regular basis. Class 8 Science Chapter 2 is a tough place for many pupils. If you are one of those students, you should get the NCERT Solutions Class 8 Science Chapter 2 pdf from the links provided on this website.

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Class 8 Science NCERT Solutions for All Chapters

Class 8 Science Chapter 2 NCERT Solution – Free PDF Download

Final examinations are approaching quickly, and if a student wants to excel, now is the time to begin studying Ncert answers for Class 8 Science Chapter 2 Microorganisms Friend and Foe. Once you’ve finished this chapter, you should move on to the next one. You may download NCERT solutions for Class 8 Science Chapter 2 Microorganisms Friend and Foe by clicking on the pdf link provided below.

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Microorganisms (Chapter 2) Class 8: Friend and Foe

Take a look around and take note of what you notice. Chairs, desks, books, technological devices, and other people are all plainly visible. What you can’t see, though, is the amazing world of microbes that are always present.

Some of these bacteria are beneficial to your health and assist you in living a healthier life. Some germs, on the other hand, inflict illness and damage to man-made materials.

This presents a slew of new issues, such as which germs are beneficial and which are harmful. What are the functions of beneficial microorganisms? What are the ways that harmful germs harm us? Students will learn the answers to all of these questions and more in Chapter 2 of Science Class 8.

Also Check Other Subjects As Well:

A weighted average of Ch 2 Science Class 8 marks

Students may be asked questions from this chapter for one, two, three, four, or even five points. Students should solve all of the NCERT questions and practice all of the diagrams several times. The strategy needed to answer any question would be determined by the total score. As a result, a student must practice a wide range of questions from a variety of credible sources.

Benefits of NCERT Solutions Class 8 Science Chapter 2

INFINITY LEARN has been able to assist students with Class 8 Science Chapter 2 solutions with the help of our excellent professors. There are numerous advantages to using this tool for pupils. Some of these advantages are listed below.

Highly accurate solutions have been prepared by a team of subject specialists.
CBSE guidelines have been strictly followed to answer all the questions
Students can easily view the answer plus the detailed descriptions of every question
The solutions are available in a PDF file that can be downloaded on any device for free.
Following the solutions and guidelines would allow the students to get maximum marks.

These benefits will ensure that students are able to grow and become better learners.

FAQs on NCERT Solutions for Class 8 Science Chapter 2

What is the main focus of NCERT Class 8 Science Chapter 2?

This chapter explores the role of microorganisms in our lives, discussing how they can be both beneficial and harmful.

What are microorganisms?

Microorganisms, often referred to as microbes, are tiny living organisms that cannot be seen with the naked eye.

How are microorganisms classified in this chapter?

Microorganisms are classified into four major categories: bacteria, viruses, fungi, and protozoa.

What are the beneficial roles of microorganisms?

Microorganisms have several positive roles, including in food production, medicine, waste management, and even in agriculture.

How can microorganisms be harmful?

Microorganisms can cause diseases in humans, animals, and plants, leading to infections and other health issues.

Can you provide examples of beneficial microorganisms?

Yes, some examples are bacteria used in curd formation, yeast in bread-making, and nitrogen-fixing bacteria in soil.

How do microorganisms spoil food?

Microorganisms can spoil food by breaking it down, causing unpleasant odors, tastes, and textures.

Why are antibiotics important?

Antibiotics are substances that can kill or inhibit the growth of harmful bacteria, helping to treat bacterial infections.