Microbes and Human Welfare MCQs for NEET — Botany Questions with Answers

A: Lactobacillus is a bacterium which is used for production of lactic acid commercially.

B: Trichoderma polysporum is a species of fungus whose commercial product is Cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients.

C: Yeast (fungus), Monascus purpureus is a species of mold that is purplish-red in colour. It has been commercialised as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.

D: Penicillin is an effective antibiotic produced by Penicillium notatum.

Rhizobium bacteria in association with roots of leguminous plants fix Atmospheric nitrogen into organic forms, which is used by the plant as nutrient. Azotobacter and Azospirillum are free-living bacteria enriching the nitrogen content of the soil. Whereas Lactobacillus is a lactic acid producing bacteria.

The technology of biogas production was developed in India mainly due to the efforts of Indian Agricultural Research Institute (IARI) and Khadi and Village Industries Commission (KVIC).

Microbes are widely used in synthesis of :

1. Antibiotics like Penicillin.

2. Fermented beverages like wine and beer.

3. Enzymes like lipases and chemicals like citric acid and butyric acid.

4. Bioactive molecules like Cyclosporin A.

Production on an industrial scale requires growing microbes in very large vessels called fermentors.

Saccharomyces cerevisiae is used for fermenting malted cereals and fruit juices, to produce ethanol and beverages.

The dough, which is used for making foods such as dosa and idli is also fermented by bacteria. The puffed-up appearance of dough is due to the production of CO₂ gas by the process of fermentation.

Alexander Fleming while working on Staphylococci bacteria, once observed a mould growing in one of his unwashed culture plates around which Staphylococci could not grow. He found out that it was due to a chemical produced by the mould and he named it Penicillin after the mould Penicillium notatum.

Cyclosporin A, that is used as an immunosuppressive agent in Organ-transplant patients, is produced by the fungus Trichoderma polysporum.

Primary treatment basically involve physical removal of particles – large and small – from the sewage through filtration and sedimentation. Firstly, floating debris is removed by sequential filtration. Then the grit (soil and small pebbles) are removed by sedimentation.