Important Questions for Class 12 Chapter 10 - Microbes in Human Welfare

Biology is a tough subject. Do you think so? It is a very common notion among students to think that science is tough. However, with the right kind of attention and preparation, you can achieve good scores in biology every time. Whether you are preparing for the final board exam or any competitive exam, all you need to do is practice. Download now!

Important questions based on NCERT syllabus for Chapter 10 - Microbes in Human Welfare:

Question-1: Why are floes important in biological treatment of waste water?

Solution: Secondary treatment or Biological treatment: The primary effluent is passed into large aeration tanks where it is constantly agitated mechanically and air is pumped into it. This allows vigorous growth of useful aerobic microbes into floes (masses of bacteria associated with fungal filaments to form mesh like structures). While growing, these microbes consume the major part of the organic matter in the effluent. This significantly reduces the BOD (biochemical oxygen demand) of the effluent.

Question-2: Name the scientists who were credited for showing the role of Penicillin as an antibiotic.

Solution: Its full potential as an effective antibiotic was established much later by Ernest Chain and Howard Florey. This antibiotic was extensively used to treat American soldiers wounded in World War II. Fleming, Chain and Florey were awarded the Nobel Prize in 1945, for this discovery.

Question-3: How do bioactive molecules of fungal origin help in restoring good health of humans?

Solution: A bioactive molecule, cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Trichoderma polysporum. Statins produced by the yeast Monascus purpureus have been commercialised as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.