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Microorganisms: Friend and Foe
Tick the correct answer: (a) Yeast is used in the production of &n...

Tick the correct answer: (a) Yeast is | Class 8 Science Chapter Microorganisms: Friend and Foe, Microorganisms: Friend and Foe NCERT Solutions

Welcome to the NCERT Solutions for Class 8 Science - Chapter Microorganisms: Friend and Foe. This page offers a step-by-step solution to the specific question from Exercise 1, Question 2: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 2:

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

(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

Answer:

(a) (ii) Alcohol

Yeast is used in the production of alcohol. This process is known as fermentation.

(b) (ii) Streptomycin

Streptomycin is an antibiotic, it is used to relieve the pain and kills other disease causing microorganisms.

Malaria is caused by a mosquito. The carrier of Malaria causing protozoan is Female Anopheles mosquito.

(d) (ii) Housefly

The most common carrier of communicable disease is housefly. It spreads the disease causing microorganisms.

(e) (iii) Growth of yeast cells

This process is called as fermentation. The dough rises due to the increased growth of yeast cells.

(f) (iii) Fermentation

The conversion of sugar into alcohol with the help of yeast cells is called as fermentation.

Other Questions of Chapter Microorganisms: Friend and Foe

Fill in the blanks:

(a) Microorganisms can be seen with the help of a ____________.
(b) Blue green algae fix __________ directly from air to enhance fertility of soil.
(c) Alcohol is produced with the help of __________.
(d) Cholera is caused by __________.

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

Write a short paragraph on the harms caused by microorganisms.

Match the organisms in Column I with their action in Column II.
Column I Column II
(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

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

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

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

What are the major groups of microorganisms?

Popular questions of class 8 Science

Describe with the help of a diagram an instrument which can be used to detect a charged body.

Sketch larynx and explain its function in your own words.

Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.

Make a labelled diagram of a candle flame.

What is metamorphosis? Give examples.

The following Table shows the total power shortage in India from 1991– 1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.

Describe the construction of a kaleidoscope.

Make sketches of animal and plant cells. State three differences between them.

What is a constellation? Name any two constellations.

Complete the crossword with the help of clues given below:
Across
1. This is necessary for photosynthesis.
3. Term for component present in the cytoplasm.
6. The living substance in the cell.
8. Units of inheritance present on the chromosomes.

Down
1. Green plastids.
2. Formed by collection of tissues.
4. It separates the contents of the cell from the surrounding medium.
5. Empty structure in the cytoplasm.
7. A group of cells.

Recently Viewed Questions of Class 8 Science

How are babies produced through IVF technique? What are such babies called?

What is menstruation? Explain.

Do all the stars in the sky move? Explain.

Should the handle and bristles of a tooth brush be made of the same material? Explain your answer.

Suggest three measures to protect ourselves from lightning.

Explain how the use of CNG in automobiles has reduced pollution in our cities.

Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon is attracted by another charged balloon?

‘Avoid plastics as far as possible’. Comment on this advice.

Select the correct word from the following list and fill in the blanks.
float, water, crop, nutrients, preparation

(a) The same kind of plants grown and cultivated on a large scale at a place is called _____________.
(b) The first step before growing crops is _____________ of the soil.
(c) Damaged seeds would _____________ on top of water.
(d) For growing a crop, sufficient sunlight and _____________ and _____________ from the soil are essential.

A blacksmith hammers a hot piece of iron while making a tool. How does the force due to hammering affect the piece of iron?

Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

Read the question carefully and focus on the core concept being asked.
Reference examples and data from the chapter when answering questions about Microorganisms: Friend and Foe.
Review previous year question papers to get an idea of how such questions may be framed in exams.
Practice answering questions within the time limit to improve your speed and accuracy.
Discuss your answers with your teachers or peers to get feedback and improve your understanding.

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