AIIMS Botany Microbes in Human Welfare Class 12 Questions

Which of the following is correct about biogas –

Assertion: The uptake of DNA during transformation is an active, energy requiring process. Reason: Transformation occurs only in those bacteria, which possess the enzymatic machinery involved in the active uptake and recombination.

Which of the following is correct?

Select the correct one –

Match Column-I (microbes) to the Column-II (biological products) and select the option having correct matching.

Assertion: Besides curdling of milk, LAB also improve its nutritional quality, by increasing vitamin – B₁₂. Reason: LAB check disease causing microbes when it is present in human stomach.

Assertion: Pili are tubular structures present in bacteria which help in conjugation. Reason: Formation of pili is controlled by F⁺ or fertility factor.

Assertion: Curdling is required in the manufacture of cheese. Reason: Lactic acid bacteria are used for the purpose.

The antibiotics have no effect on viruses because

Which of the following microbes is correctly paired with its function?

Assertion: While working on Staphylococci, Alexander Fleming observed that Penicillium notatum inhibits the growth of the bacteria.

Reason: This inhibiting chemical was commercially extracted and its full potential was established by Alexander Fleming.

Assertion: Saccharomyces cerevisiae produces acetic acid. Reason: Trichoderma polysporum produces blood cholesterol lowering agent.

Which of the following statements is incorrect regarding fermentation?

Which of the following statements is correct?

Assertion : Amount of organic biodegradable compounds present in water is measured by the BOD of that water. Reason : During biodegradation of biodegradable organic compounds, oxygen is released by bacteria.

Select the correct statement.

Biological Oxygen Demand (BOD) is a measure of:

Azolla is used as a biofertilizer because it

Assertion : Yeasts such as Saccharomyces cerevisiae are used in baking industry.

Reason : Carbon dioxide produced during fermentation causes bread dough to rise by thermal expansion.

Cyclosporine is used as

In 1929, a scientist discovered an antibiotic which was found very effective. The name of the scientist and the antibiotic, respectively are

Cyanobacteria helps farmers by

Assertion: Fruit juices taste bitter on being kept for some time.

Reason: Microorganisms of the air spoil it quickly.