Information about microbes bases on 8th chapter of science and technology of stander 9th
Answers
Maharashtra Board Class 9 Science Chapter 8- Important Questions & Answers
1. What are Lactobacilli?
Answer: A minute and rectangular in shape bacteria (blue rod-shaped organism) that are anaerobic bacteria that can produce energy without the use of oxygen are called Lactobacilli.
2. How is yoghurt made from milk? What exactly happens in this process?
Answer: The lactobacilli converts the lactose, that is the sugar in the milk, into lactic acid via the process known as fermentation. Following this, the pH of milk reduces, resulting in the coagulation of milk proteins. This also separates the milk proteins from the other milk constituents. This is what occurs when milk is changed to yoghurt. Yoghurt has specific sour taste because of lactic acid and the low pH helps to destroy the harmful microbes found in the milk.
3. What are some of the milk products obtained by fermentation of milk?
Answer: There are several milk products that can be obtained by fermentation of milk. They include ghee, yoghurt, cheese, buttermilk, shrikhand and more.
4. What are some of the uses of Lactobacilli?
Answer: Given here are some of the uses of Lactobacilli:
Lactobacilli fermentation is used to produce cider, cocoa, vegetable pickles and so on on a large scale
Along with some other microbes, Lactobacilli are used to treat abdominal infection
Lactobacilli is used to ferment leavened fodder given to domestic cattle such as cows and buffalos
Lactobacilli fermentation process is useful to manufacture wine and certain kinds of breads
5. Write the names of microbes found in the following food materials.
(yoghurt, bread, root nodules of leguminous plants, idli, dosa, spoiled potato curry.)
Answer: Given are the microbes present in the following food materials
Yoghurt- Microbe found in it is Lactobacillus
Bread- Saccharomyces is the microbe found in it
Root nodules of Leguminous plants- The microbe found is Rhizobium
Idli- Lactobacillus is found in it
Dosa- Microbe is Lactobacillus
Spoiled potato curry- Clostridium is one of the microbes found
6. Identify the odd one out from Pneumonia, diphtheria, chicken pox, cholera. Why is it the odd one out?
Answer: Chicken pox is the odd one out as it is a viral disease, whereas the rest are all bacterial diseases.
7. Root rot, rust (tambera), rubella, mozaic. Which amongst these is the odd one out. State the reason.
Answer: Rubella is the odd one out. Root rot, rust (tambera) and mozaic are all names of plant disease, while rubella is a human disease.
8. Which is the odd one from Lactobacilli, rhizobia, yeast and clostridia? Why?
Answer: From this list, Rhizobia is the odd one out. Lactobacilli, Yeast and Clostridia are all bacterias associated with human food products, while Rhizobia is a bacteria related to plants.
9. Foam accumulates on the surface of ‘dal’ kept for a long time in summer. What is the scientific reason for this?
Answer: Food stuff that is kept for a longer time in the summer is favourable for the growth of microbes, which releases some gas as it’sby-product. This gas creates foam on the surface of food stuffs that have more water content, such as dal.
10. Give scientific reason for why naphthalene balls are kept with clothes to be put away.
Answer; Naphthalene balls are kept with clothes to protect them from insects. However, over a period of time, they disappear without leaving any residue as a result of the sublimation process.