Get, detailed solutions to the questions of the chapter Microbes in Human Welfare from NCERT textbooks. The objective is to helping students regarding the pattern of answering the question as per the cbse latest marking scheme.Cbse.jagranjosh.com provided you NCERT solutions for classes 12th math and science subjects.
Some questions of this chapter are given here
Q. Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why?
Answer. I will take curd to the lab. A small drop of curd contains millions of Lactobacillus bacteria which can be easily seen under microscope.
Q. Give examples to prove that microbes release gases during metabolism.
Answer. When any bacteria grow on any material, it uses that material as their food and start metabolism of that material and release products. Puffed appearance of dough of dosa is due to the release of gases like CO2 by the bacteria growing on them. Large holes on Swiss cheeses are also due to bacteria grown on them.
Q. In which food would you find lactic acid bacteria? Mention some of their useful applications.
Answer. In curd we found Lactic acid bacteria (LAB). These bacteria can convert milk into curd. LAB also found in our stomach which checks the growth of harmful bacteria in our stomach. LAB increases the amount of vit B12 in curd.
Q. Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve use of microbes.
Answer. Product of wheat: Cakes, bread etc. Product of rice: Dosa, idli etc. Product of Bengal gram: Khandvi, dhokla etc.
Q. In which way have microbes played a major role in controlling diseases caused by harmful bacteria?
Answer. Antibiotics are used to treat amny diseases which are caused by harmful bacteria. As we know, antibiotics the chemical substances which are produced by using microorganisms and these antibiotics can kill or reduce the growth of diseases causing organisms. Ex – penicillin.