Answer Briefly
1. Where are microorganisms found in nature?
2. How does the bacterium Lactobacillus help in curd formarior?
3. In bread making, why does the dough rise when yeast is added to it ?
4. Write briefly about the commercial uses of microorganisms in the production of alcohol?
5. What is the role of bacteria in increasing soil fertility?
6. What general precautions/measures should be taken to prevent microbial diseases?
7. Mention the various advantages of food preservation.
8. How will you preserve the following food items?
(a) Milk
(b) Jam
(c) Cereals
(d) Pickles
(e) Dry fruit
(f) Cauliflower
Answers
Answer:
1 in all places
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Answer:
Explanation:Take ½ kg flour (atta or maida), add some sugar and mix with Fig. 2.5 : Viruses
NCERT Class VIII Science Chapter 2 Microorganisms - Friend and Foe
Yeast reproduces rapidly and produces carbon dioxide during
respiration. Bubbles of the gas fill the dough and increase its volume (Fig. 2.6). This is the basis of the use of yeast in the baking industry for making breads, pastries and cakes.
Commercial Use of Microorganisms Microorganisms are used for the large scale production of alcohol, wine and acetic acid (vinegar). Yeast is used for commercial production of alcohol and wine. For this purpose yeast is grown on natural sugars present in grains like barley, wheat, rice and crushed fruit juices, etc.
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