Biology MCQ
#10 Biology Class XII- Microbes in Human Welfare (NEET, MHTCET) MCQ
1) The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is [NCERT Exemplar]
Answer(a) vitamin C(b) vitamin D(c) vitamin B12(d) vitamin E.
(c) vitamin B12
2) A common biocontrol agent for the control of plant diseases is
Answer(a) baculovirus(b) Bacillus thuringiensis(c) Glomus(d) Trichoderma
(a) baculovirus
3) Secondary sewage treatment is mainly a
Answer(a) physical process(b) mechanical process(c) chemical process(d) biological process
(d) biological process
4) An organism used as a biofertilizer for raising soyabean crop is
Answer(a) Azotobacter(b) Azospirillum(c) Rhizobium(d) Nostoc
(c) Rhizobium
5) Monascus purpureus is a yeast used commercially in the production of
Answer(a) ethanol(b) streptokinase for removing clots from the blood vessels(c) citric acid(d) blood cholesterol lowering statins.
(d) blood cholesterol lowering statins.
6) A good producer of citric acid is
Answer(a) Clostridium(b) Sacchaaromyces(c) Aspergillus(d) Pseudomonas.
(c) Aspergillus
7) Wastewater treatment generates a large quantity of sludge, which can be treated by [NCERT Exemplar]
Answer(a) anaerobic digesters(b) floc(c) chemicals(d) oxidation pond
(a) anaerobic digesters
8) Select the correct statement from the following
Answer(a) Biogas is produced by the activity of aerobic bacteria on animal waste(b) Methanobacterium is an aerobic bacterium found in rumen of cattle(c) Biogas, commonly called gobar gas, is pure methane(d) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.
(d) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.
9) Methanogenic bacteria are not found in [NCERT Exemplar]
Answer(a) rumen of cattle(b) gobar gas plant(c) bottom of water-logged paddy fields(d) activated sludge.
(d) activated sludge.
10) Match the following list of bacteria and their commercially important products [NCERT Exemplar]
Bacterium Product
A. Aspergillus niger (i) Lactic acid
B. Acetobacter aceti (ii) Butyric acid
C. Clostridium butylicum (iii) Acetic acid
D. Lactobacillus (iv) Citric acid
Choose the correct match.
Answer(a) A-(ii), B-(iii), C-(iv), D-(i)(b) A-(ii), B-(iv), C-(iii), D-(i)(c) A-(iv), B-(iii), C-(ii), D-(i)(d) A-(iv), B-(i), C-(iii), D-(ii)
(c) A-(iv), B-(iii), C-(ii), D-(i)
11) Bottled fruit juices from market are clearer than that at home because of
Answer(a) antibiotics(b) hormones(c) enzymes(d) filtration
(c) enzymes
12) Match the following list of bioactive substances and their roles [NCERT Exemplar]
Bioactive Substance Role
A. Statin (i) Removal of oil stains ]
B. Cyclosporin A (ii) Removal of clots from blood vessels
C. Streptokinase (iii) Lowering of blood cholesterol
D. Lipase (iv) Immuno-suppressive agent
Choose the correct match.
Answer(a) A-(ii), B-(iii), C-(i), D-(iv)(b) A-(iv), B-(ii), C-(i), D-(iii)(c) A-(iv), B-(i), C-(ii), D-(iii)(d) A-(iii), B-(iv), C-(ii), D-(i)
(d) A-(iii), B-(iv), C-(ii), D-(i)
13) The primary treatment of waste water involves the removal of [NCERT Exemplar]
Answer(a) dissolved impurities(b) stable particles(c) toxic substances(d) harmful bacteria.
(b) stable particles
14) BOD of waste water is estimated by measuring the amount of [NCERT Exemplar]
Answer(a) total organic matter(b) biodegradable organic matter(c) oxygen evolution(d) oxygen consumption
(d) oxygen consumption
15) Which one of the following alcoholic drinks is produced without distillation? [NCERT Exemplar]
Answer(a) Wine(b) Whisky(c) Rum(d) Brandy
(a) Wine
16) The technology of biogas production from cow dung was developed in India largely due to the efforts of [NCERT Exemplar]
Answer(a) Gas Authority of India(b) Oil and Natural Gas Commission(c) Indian Agricultural Research Institute and Khadi & Village Industries Commission(d) Indian Oil Corporation.
(c) Indian Agricultural Research Institute and Khadi & Village Industries Commission
17) Which of these is/are symbiotic N2 fixing organisms?
Answer(a) Rhizobium(b) Clostridium(c) Azotobacter(d) All of these
(a) Rhizobium
18) The free-living fungus Trichoderma can be used for [NCERT Exemplar]
Answer(a) insects(b) biological control of plant diseases(c) controlling butterfly caterpillars(d) producing antibiotics
(b) biological control of plant diseases
19) What would happen if oxygen availability to activated sludge flocs is reduced? [NCERT Exemplar]
Answer(a) It will slow down the rate of degradation of organic matter(b) The center of flocs will become anoxic, which would cause death of bacteria and eventually breakage of flocs.(c) Flocs would increase in size as anaerobic bacteria would grow around flocs.(d) Protozoa would grow in large numbers.
(b) The center of flocs will become anoxic, which would cause death of bacteria and eventually breakage of flocs.
20) Mycorrhiza does not help the host plant in [NCERT Exemplar]
Answer(a) enhancing its phosphorus uptake capacity(b) increasing its tolerance to drought(c) enhancing its resistance to root pathogens(d) increasing its resistance to insects.
(d) increasing its resistance to insects.
21) Big holes in Swiss cheese are made by [NCERT Exemplar]
Answer(a) a machine(b) a bacterium that produces methane gas(c) a bacterium producing a large amount of carbon dioxide(d) a fungus that releases a lot of gases during its metabolic activities.
(c) a bacterium producing a large amount of carbon dioxide
22) The residue left after methane production from cattle dung is [NCERT Exemplar]
Answer(a) burnt(b) burried in land fills(c) used as manure(d) used in civil construction.
(c) used as manure
23) Methanogens do not produce [NCERT Exemplar]
Answer(a) oxygen(b) methane(c) hydrogen sulfide(d) carbon dioxide.
(a) oxygen
24) Primary treatment of sewage waste involves which processes ?
Answer(a) Filtration and incubation(b) Sedimentation and decantation(c) Filtration and sedimentation(d) Sedimentation and microbial proliferation
(c) Filtration and sedimentation
25) Activated sludge should have the ability to settle quickly so that it can [NCERT Exemplar]
Answer(a) be rapidly pumped back from sedimentation tank to aeration tank(b) absorb pathogenic bacteria present in waste water while sinking to the bottom of the settling tank(c) be discarded and anaerobically digested(d) absorb colloidal organic matter.
(a) be rapidly pumped back from sedimentation tank to aeration tank
26) Match the items in Column ‘A’ and Column ‘B’ and choose correct answer. [NCERT Exemplar]
Column IColumn II
A. Lady bird(i) Methanobacterium
B. Mycorrhiza(ii) Trichoderma
C. Biological control(iii) Aphids
D. Biogas(iv) Glomus
The correct answer is:
Answer(a) A-(ii), B-(iv), C-(iii), D-(i)(b) A-(iii), B-(iv), C-(ii), D-(i)(c) A-(iv), B-(i), C-(ii), D-(iii)(d) A-(iii), B-(ii), C-(i), D-(iv)
(b) A-(iii), B-(iv), C-(ii), D-(i)
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