Microbes in Human Welfare quiz

The large holes in Swiss cheese are due to production of CO2 by:

Citric acid is produced commercially by:

Streptokinase, used as a clot buster, is produced by:

Cyclosporin A is used as an immunosuppressive agent in organ transplant patients and is produced by:

Which of the following alcoholic beverages is produced without distillation?

The cyanobacterium that fixes atmospheric nitrogen in paddy fields is:

Biogas consists mainly of:

Primary treatment of sewage involves:

Statins, which lower blood cholesterol, are produced by the yeast:

Mycorrhiza is a symbiotic association between:

Why does curd contain more vitamin B12 than milk? Name the microbe involved. (2 marks)

How is toddy prepared? Which microbe is involved? (2 marks)

Name two enzymes produced by microbes and their uses. (2 marks)

What is activated sludge? What happens to it after secondary treatment? (2 marks)

Name the organisations in India that developed the technology of biogas production. (2 marks)

Why are bottled fruit juices clearer than homemade juices? (2 marks)

How does Trichoderma act as a biocontrol agent? (2 marks)

Why are baculoviruses considered desirable in integrated pest management programmes? (2 marks)

How do mycorrhizal fungi benefit the host plant? (2 marks)

Why does the dough used for making bread puff up? (2 marks)

The BOD of a river sample is 20 mg/L, and that of sewage entering it is 400 mg/L. If after treatment the sewage BOD is reduced by 95%, calculate the BOD of the treated effluent and compare it with the river water. (3 marks)

A biogas plant needs 25 kg of cattle dung per cubic metre of gas. A family needs 2 cubic metres of gas per day. How much dung is needed per week? If one cow gives about 10 kg of dung a day, how many cows are needed? (3 marks)

A field yields 20 quintals of rice per hectare without biofertilisers. Inoculation with cyanobacteria increases the yield by 15%. Calculate the new yield and the extra yield on 4 hectares. (3 marks)

A sewage plant treats 50 lakh litres of sewage per day. If 2% of the volume settles as primary sludge, calculate the volume of primary sludge produced per day in litres. Where does this sludge go next? (3 marks)

A culture of yeast doubles every 2 hours. Starting from 1,000 cells in a dough, how many cells will be present after 8 hours? Which gas makes the dough rise? (3 marks)

Read the passage and answer the questions. In 1928, a scientist working on Staphylococci bacteria noticed that a mould growing on one of his unwashed culture plates had prevented the bacteria from growing around it. (i) Name the scientist and the mould. (ii) Name the chemical responsible. (iii) Who later established its full potential as an antibiotic? (5 marks)

Read the passage and answer the questions. A municipal sewage plant passes primary effluent into large aeration tanks where it is constantly agitated and air is pumped in. Masses of bacteria associated with fungal filaments grow rapidly and consume the organic matter. (i) Name the masses of bacteria and fungal filaments. (ii) Why is air pumped into the tanks? (iii) How is the progress of treatment monitored? (5 marks)

Read the passage and answer the questions. A village built a gobar gas plant. Cattle dung slurry is fed into a concrete tank where bacteria break it down without oxygen. A floating cover rises as gas is produced, and the spent slurry is used as manure. (i) Name the bacteria involved. (ii) Why is the process anaerobic? (iii) State two benefits of this plant to villagers. (5 marks)

Read the passage and answer the questions. An organic farmer controls aphids by releasing ladybird beetles and controls mosquitoes in his farm pond with dragonflies. He also sprays spores of a bacterium that kills butterfly caterpillars. (i) Name the bacterium. (ii) How does it kill the caterpillars? (iii) Why is this approach better than using chemical insecticides? (5 marks)

Read the passage and answer the questions. A farmer grows pulses in rotation with wheat. Nodules on the roots of pulse plants contain bacteria that fix atmospheric nitrogen, and the following wheat crop needs less fertiliser. (i) Name the bacteria in the nodules. (ii) Name two free-living nitrogen-fixing bacteria. (iii) Why is crop rotation with pulses beneficial? (5 marks)

Describe the role of microbes in industrial production of beverages, antibiotics, chemicals and enzymes, with one example of each. Draw a labelled diagram of a fermenter or bioreactor used in such industries. (6 marks)

Describe the steps of sewage treatment with a labelled flowchart. Explain the importance of BOD and the role of anaerobic sludge digesters. (6 marks)

Draw a labelled diagram of a biogas plant. Explain how biogas is produced and why it is considered a clean fuel. (6 marks)

Explain the use of microbes as biocontrol agents with examples. Draw a chart comparing chemical pest control with biological control on four bases. (6 marks)

What are biofertilisers? Describe the role of Rhizobium, Azotobacter, Azospirillum, cyanobacteria and mycorrhiza. Draw a labelled diagram of a root nodule or a mycorrhizal root. (6 marks)