Assertion A: Wine and beer require distillation of the fermented broth. Reason R: Whisky, brandy and rum are produced by fermentation followed by distillation. Choose the correct answer.

A is not correct but R is correct

Both A and R are correct and R is the correct explanation of A

Both A and R are correct but R is not the correct explanation of A

A is correct but R is not correct

Two water samples are compared, and sample P has a much higher BOD than sample Q. What does this show?

P holds more organic matter that microbes can oxidise

P holds more dissolved oxygen than Q

Microbes in Human Welfare

11 NEET-UG practice questions on Microbes in Human Welfare, part of Botany. The first 11 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
Assertion A: Wine and beer require distillation of the fermented broth. Reason R: Whisky, brandy and rum are produced by fermentation followed by distillation. Choose the correct answer.
1. ABoth A and R are correct and R is the correct explanation of A
2. BBoth A and R are correct but R is not the correct explanation of A
3. CA is correct but R is not correct
4. DA is not correct but R is correct
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Answer: D · A is not correct but R is correct
Wine and beer are produced without distillation, so A is false. Whisky, brandy and rum are made by distilling the fermented broth, so R is correct.
- A: A is false, so R cannot explain it.
- B: A is false, so both cannot be correct.
- C: R is true; A is the false part.
Remember this
No distillation for wine and beer; distillation for whisky, brandy and rum.
Question 2 · Easy
The large holes in Swiss cheese are due to carbon dioxide released by which microbe?
1. APropionibacterium sharmanii
2. BAcetobacter aceti
3. CSaccharomyces cerevisiae
4. DLactobacillus
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Answer: A · Propionibacterium sharmanii
Propionibacterium sharmanii produces a large amount of CO₂ during ripening, and the gas forms the holes.
- B: This bacterium produces acetic acid.
- C: This yeast is used in bread and alcoholic drinks.
- D: This bacterium turns milk into curd.
Remember this
Swiss cheese holes come from CO₂ of Propionibacterium sharmanii; Roquefort is ripened by specific fungi.
Question 3 · Medium
Two water samples are compared, and sample P has a much higher BOD than sample Q. What does this show?
1. AP is cleaner than Q
2. BP holds more dissolved oxygen than Q
3. CP holds more organic matter that microbes can oxidise
4. DP holds fewer microbes than Q
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Answer: C · P holds more organic matter that microbes can oxidise
BOD is the amount of oxygen consumed if all the organic matter in one litre of water were oxidised by bacteria. A higher BOD means more organic matter and greater polluting potential.
- A: A high BOD marks more polluted water.
- B: BOD measures oxygen demand, not the oxygen present.
- D: A high BOD is met by microbes feeding on plentiful organic matter.
Remember this
Higher BOD means more organic matter and greater polluting potential; secondary treatment lowers it.
Question 4 · Medium
Match List-I with List-II. List-I (product) A. Streptokinase B. Cyclosporin A C. Statins D. Penicillin List-II (use) I. Immunosuppressive agent in organ transplants II. Lowering blood cholesterol III. Removing clots from blood vessels IV. Killing disease-causing bacteria
1. AA-III, B-I, C-II, D-IV
2. BA-I, B-III, C-II, D-IV
3. CA-III, B-II, C-I, D-IV
4. DA-IV, B-I, C-II, D-III
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Answer: A · A-III, B-I, C-II, D-IV
Streptokinase dissolves clots, cyclosporin A suppresses immunity in transplant patients, statins lower cholesterol by competing with the enzyme for its synthesis, and penicillin is an antibiotic.
- B: This swaps streptokinase and cyclosporin A.
- C: This swaps cyclosporin A and statins.
- D: This swaps streptokinase and penicillin.
Remember this
Clot buster streptokinase, immunosuppressant cyclosporin A, cholesterol-lowering statins from Monascus, antibiotic penicillin from Penicillium.
Question 5 · Medium
Match List-I with List-II. List-I (acid) A. Citric acid B. Acetic acid C. Butyric acid D. Lactic acid List-II (microbe) I. Clostridium butylicum II. Aspergillus niger III. Lactobacillus IV. Acetobacter aceti
1. AA-II, B-III, C-I, D-IV
2. BA-II, B-IV, C-I, D-III
3. CA-II, B-IV, C-III, D-I
4. DA-IV, B-II, C-I, D-III
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Answer: B · A-II, B-IV, C-I, D-III
Citric acid comes from the fungus Aspergillus niger. The bacteria Acetobacter aceti, Clostridium butylicum and Lactobacillus give acetic, butyric and lactic acids respectively.
- A: This swaps acetic and lactic acid sources.
- C: This swaps butyric and lactic acid sources.
- D: This swaps citric and acetic acid sources.
Remember this
Citric acid is from a fungus, Aspergillus; acetic, butyric and lactic acids are from bacteria.
Question 6 · Hard
In a sewage plant, the air supply to the secondary treatment tank fails for a long period. What is the expected result?
1. ABOD of the effluent falls faster because oxygen is no longer being used up
2. BBOD of the effluent stays high because the flocs consume less organic matter
3. CGrit and large debris start to pass into the tank
4. DPrimary sludge starts to form in place of activated sludge
Answer and explanation in LearnFree account
Question 7 · Medium
Given below are two statements: Statement I: Primary sewage treatment depends mainly on aerobic microbial flocs. Statement II: Anaerobic digestion of activated sludge gives a gas made mainly of oxygen and nitrogen. Choose the correct answer.
1. AStatement I is incorrect but Statement II is correct
2. BStatement I is correct but Statement II is incorrect
3. CBoth Statement I and Statement II are incorrect
4. DBoth Statement I and Statement II are correct
Answer and explanation in LearnFree account
Question 8 · Easy
Which microbe gives the 'clot buster' used to remove clots from blood vessels?
1. AStreptococcus
2. BClostridium butylicum
3. CTrichoderma polysporum
4. DMonascus purpureus
Answer and explanation in LearnFree account
Question 9 · Hard
Match List-I with List-II. List-I (organism) A. Rhizobium B. Azospirillum C. Glomus D. Anabaena List-II (role as biofertiliser) I. Free-living nitrogen fixer in soil II. Autotrophic nitrogen fixer in paddy fields III. Nitrogen fixer in root nodules of legumes IV. Fungal partner that raises phosphorus uptake
1. AA-I, B-III, C-IV, D-II
2. BA-III, B-I, C-IV, D-II
3. CA-III, B-II, C-IV, D-I
4. DA-III, B-I, C-II, D-IV
Answer and explanation in LearnFree account
Question 10 · Medium
Which of these statements about biocontrol are correct? A. Ladybird beetles help to control aphids. B. Dragonflies help to control mosquitoes. C. Bt toxin is released in the gut of caterpillars that eat the spores. D. Baculoviruses are broad-spectrum agents that also kill non-target insects.
1. AB, C and D only
2. BA, B and C only
3. CA and B only
4. DA, C and D only
Answer and explanation in LearnFree account
Question 11 · Easy
Which genus forms mycorrhiza with plant roots?
1. AAnabaena
2. BGlomus
3. CRhizobium
4. DAzospirillum
Answer and explanation in LearnFree account

Microbes in Human Welfare

Assertion A: Wine and beer require distillation of the fermented broth. Reason R: Whisky, brandy and rum are produced by fermentation followed by distillation. Choose the correct answer.

The large holes in Swiss cheese are due to carbon dioxide released by which microbe?

Two water samples are compared, and sample P has a much higher BOD than sample Q. What does this show?

Match List-I with List-II. List-I (product) A. Streptokinase B. Cyclosporin A C. Statins D. Penicillin List-II (use) I. Immunosuppressive agent in organ transplants II. Lowering blood cholesterol III. Removing clots from blood vessels IV. Killing disease-causing bacteria

Match List-I with List-II. List-I (acid) A. Citric acid B. Acetic acid C. Butyric acid D. Lactic acid List-II (microbe) I. Clostridium butylicum II. Aspergillus niger III. Lactobacillus IV. Acetobacter aceti

In a sewage plant, the air supply to the secondary treatment tank fails for a long period. What is the expected result?

Given below are two statements: Statement I: Primary sewage treatment depends mainly on aerobic microbial flocs. Statement II: Anaerobic digestion of activated sludge gives a gas made mainly of oxygen and nitrogen. Choose the correct answer.

Which microbe gives the 'clot buster' used to remove clots from blood vessels?

Which of these statements about biocontrol are correct? A. Ladybird beetles help to control aphids. B. Dragonflies help to control mosquitoes. C. Bt toxin is released in the gut of caterpillars that eat the spores. D. Baculoviruses are broad-spectrum agents that also kill non-target insects.

Which genus forms mycorrhiza with plant roots?