NCERT Solutions Science for Class 8 Chapter 2 MICROORGANISMS FRIEND AND FOE

NCERT Solutions Science for Class 8 Chapter 2 MICROORGANISMS FRIEND AND FOE available free in eteacherg.com। Here We learn class8 science chapter 2 question answer concept of Microbe Friends and Enemies and and solve questions. NCERT Solutions Science for Class 8 Chapter 2 MICROORGANISMS FRIEND AND FOE. NCERT science chapter 2 class 8 are part of NCERT class 8 science solution. Here we have given class8 science chapter 2.

NCERT Solutions Science for Class 8 Chapter 2 MICROORGANISMS FRIEND AND FOE। Below these solutions consist of answers to all the important questions in NCERT book class 8th science chapter 2. Here we solve Ncert class 8 science chapter 2 question answer concepts all questions with easy method with expert solutions. It help students in their study, home work and preparing for exam. Soon we provide

NCERT class8 science chapter 2 question and answers. is provided here according to the latest NCERT (CBSE) guidelines. Students can easily access which include important Chapters and deep explanations provided by our expert. Get CBSE in free PDF here. ncert solutions for class 8th science book pdf also available Click Here or you can download official NCERT website. You can also See NCERT Solutions for class 8 science book pdf with answers all Chapter to Click Here.

NCERT Solutions Science for Class 8 Chapter 2 MICROORGANISMS FRIEND AND FOE

class8 science chapter 2

NCERT Solutions Science for Class 8 Chapter 2 MICROORGANISMS FRIEND AND FOE

science for class 8 chapter 2 question answer

1. Fill in the blanks.
(a) Microorganisms can be seen with the help of a ____________.
(b) Blue green algae fix __________ directly from air and enhance fertility of soil.
(c) Alcohol is produced with the help of __________.
(d) Cholera is caused by __________.
Answer –
(a) Microorganisms can be seen with the help of a microscope.
(b) Blue green algae fix nitrogen directly from air and enhance fertility of soil.
(c) Alcohol is produced with the help of yeast.
(d) Cholera is caused by bacteria.

2. Tick the correct answer.
(a) Yeast is used in the production of

(i) sugar (ii) alcohol (iii) hydrochloric acid (iv) oxygen

Answer : (ii) alcohol

(b) The following is an antibiotic

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

Answer : (ii) Streptomycin

(c) Carrier of malaria-causing protozoan is

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

Answer : (i) female Anopheles mosquito

(d) The most common carrier of communicable diseases is

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

Answer : (ii) housefly

(e) The bread or idli dough rises because of

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

Answer : (iii) growth of yeast cells

(f) The process of conversion of sugar into alcohol is called

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

Answer : (iii) fermentation

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

A 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

Answer :

A B
(i) Bacteria (e) Causing cholera
(ii) Rhizobium (a) Fixing nitrogen
(iii) Lactobacillus (b) Setting of curd
(iv) Yeast (c) Baking of bread
(v) A protozoan (d) Causing malaria
(vi) A virus (f) Causing AIDS

4. Can microorganisms be seen with the naked eye? If not, how can they be seen?
Answer : No, we can’t see microorganism with the naked eye. We can see microorganism with the help of microscope.

5. What are the major groups of microorganisms?
Answer : Microorganisms are classified into four major groups. These groups are bacteria, fungi, protozoa and some algae.
Microorganisms are divided into four main classes, which are as follows –
(i) Bacteria – Micrococcus
(ii) Fungi – zygomycotic
(iii) Protozoa – Amoeba
(iv) Algae – Diatoms

6. Name the microorganisms which can fix atmospheric nitrogen in the soil.
Answer : Certain bacteria and blue green algae present in the soil fix nitrogen from the atmosphere and convert it into compounds of nitrogen. Rhizobium bacteria fix atmospheric nitrogen in the soil.

7. Write 10 lines on the usefulness of microorganisms in our lives.
Answer :
(i) They are helpful in the production of pickles, cheese and other food items. It is helpful in fermentation.
(ii) They are used to keep the environment clean and balanced.
(iii) They are used in making vaccines.
(iv) They are used for making alcohol, alcohol and acetic acid.
(v) Microorganisms are used in agriculture to increase the fertilizer capacity of the soil.
(vi) Rhizobium bacteria fix atmospheric nitrogen in the soil. Due to which the amount of nitrogen in the atmosphere remains constant.
(vii) It is used to protect plants from diseases.
(viii) It is useful in protecting humans and animals from diseases.
(ix) They are used in the manufacture of medicines.
(x) They are used in making bread, cake and curd.

8. Write a short paragraph on the harmful effects of microorganisms.
Answer : Following are the disadvantages of microorganisms:
(i) Many microorganisms cause diseases in humans and animals.
(ii) Some fungi cause skin diseases like ringworm, scabies, itching.
(iii) Some bacteria reduce the fertility of the land by converting nitrates of the soil into nitrogen.
(iv) Some fungi cause diseases in plants by infecting them.
(v) Some microorganisms destroy food by making it toxic.
(vi) Some bacteria destroy plants and food.
(vii) Some fungi destroy our leather and wood and food items.
(viii) Many bacteria and viruses cause serious diseases like malaria, AIDS.

9. What are antibiotics? What precautions must be taken while taking antibiotics?
Answer :
Medicines that kill and inhibit the growth of disease-causing microorganisms are called antibiotics or antibiotics.
Precautions to be taken while taking antibiotics
Antibiotics should be taken with the advice of the doctor and the course given by the doctor should be completed, otherwise the antibiotic medicines are not as effective the next time they are needed.

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