Students are advised to practice the NCERT MCQ Questions for Class 12 Biology Chapter 10 Microbes in Human Welfare with Answers Pdf free download is available here. MCQ Questions for Class 12 Biology with Answers are prepared as per the Latest Exam Pattern. Students can solve these Microbes in Human Welfare Class 12 MCQs Questions with Answers and assess their preparation level.
Microbes in Human Welfare Class 12 MCQs Questions with Answers
Solving the Microbes in Human Welfare Multiple Choice Questions of Class 12 Biology Chapter 10 MCQ can be of extreme help as you will be aware of all the concepts. These MCQ Questions on Microbes in Human Welfare Class 12 with answers pave for a quick revision of the Chapter thereby helping you to enhance subject knowledge. Have a glance at the MCQ of Chapter 10 Biology Class 12 and cross-check your answers during preparation.
Select the correct answer
Question 1.
The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is:
(a) Vitamin C
(b) Vitamin D
(c) Vitamin B12
(d) Vitamin E.
Answer
Answer: (c) Vitamin B12
Question 2.
Waste water treatment generates a large quantity of sludge, which can be treated by:
(a) digesters
(b) activated sludge
(c) chemicals
(d) oxidation pond.
Answer
Answer: (d) oxidation pond.
Question 3.
Methanogenic bacteria are not found in:
(a) rumen of cattle
(b) gobar gas plant
(c) bottom of water logged paddy fields
(d) activated sludge.
Answer
Answer: (d) activated sludge.
Question 4.
Match the following list of bacteria and their commercially important products:
| Column I | Column II |
| (i) Aspergillus niger | (a) Lactic acid |
| (ii) Acetobacter aceti | (b) Butyric acid |
| (iii) Clostridium butylicum | (c) Acetic acid |
| (iv) Lactobacillus | (d) Citric acid |
Choose the correct match:
(a) i-b, ii-c, iii-d, iv-a
(b) i-b, ii-d, iii-c, iv-a
(c) i-d, ii-c, iii-b, iv-a
(d) i-d, ii-a, iii-c, iv-b.
Answer
Answer: (c) i-d, ii-c, iii-b, iv-a
Question 5.
Match the following list substances and their roles:
| Column I | Column II |
| (i) Statin | (a) Removal of oil stains |
| (ii) Cyclosporin A | (b) removal of clots from blood vessels |
| (iii) Streptokinase | (c) Lowering of blood cholesterol |
| (iv) Lipase | (d) Immuno-suppressive agent |
Choose the correct match :
(a) i-b, ii-c, iii-a, iv-d
(b) i-d, ii-b, iii-a, iv-c
(c) i-d, ii-a, iii-d, iv-c
(d) i-c, ii-d, iii-b, iv-a.
Answer
Answer: (d) i-c, ii-d, iii-b, iv-a.
Question 6.
The primary treatment of waste water involves the removal of:
(a) dissolved impurities
(b) stable particles
(c) toxic substances
(d) harmful bacteria.
Answer
Answer: (b) stable particles
Question 7.
BOD of waste water is estimated by measuring the amount of:
(a) total organic matter
(b) biodegradable organic matter
(c) oxygen evolution
(d) oxygen consumption.
Answer
Answer: (d) oxygen consumption.
Question 8.
Which one of the following alcoholic drinks is produced without distillation?
(a) Wine
(b) Whisky
(c) Rum
(d) Brandy.
Answer
Answer: (a) Wine
Question 9.
The technology of biogas production from cow dung was developed in India largely due to the efforts of:
(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.
Answer
Answer: (c) Indian Agricultural Research Institute and Khadi & Village Industries Commission
Question 10.
The free-living fungus Trichoderma can be used for:
(a) killing insects
(b) biological control of plant diseases
(c) controlling butterfly caterpillars
(d) producing antibiotics.
Answer
Answer: (b) biological control of plant diseases
Question 11.
What would happen if oxygen availability to activated sludge floes is reduced?
(a) It will slowdown the rate of degradation of organic matter.
(b) The centre of floes will become anoxic, which would cause death of bacteria and eventually breakage of floes.
(c) Floes would increase in size as anaerobic bacteria would grow around floes.
(d) Protozoa would grow in large numbers.
Answer
Answer: (b) The centre of floes will become anoxic, which would cause death of bacteria and eventually breakage of floes.
Question 12.
Mycorrhiza does not help the host plant in:
(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.
Answer
Answer: (d) Increasing its resistance to insects.
Question 13.
Which one of the following is not a nitrogen-fixing organism?
(a) Anabaem
(b) Nostoc
(c) Azotobacter
(d) Pseudomonas.
Answer
Answer: (d) Pseudomonas.
Question 14.
Big holes in Swiss cheese are made by a:
(a) machine
(b) bacterium that produces methane gas
(c) bacterium producing a large amount of carbon dioxide
(d) fungus that releases a lot of gases during its metabolic activities.
Answer
Answer: (c) bacterium producing a large amount of carbon dioxide
Question 15.
The residue left after methane production from cattle dung is:
(a) burnt
(b) buried in land-fills
(c) used as manure
(d) used in civil construction.
Answer
Answer: (c) used as manure
Question 16.
Methanogens do not produce:
(a) oxygen
(b) methane
(c) hydrogen sulphide
(d) carbon dioxide.
Answer
Answer: (a) oxygen
Question 17.
Activated sludge should have the ability to settle quickly so that it can:
(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
Answer
Answer: (a) be rapidly pumped back from sedimentation tank to aeration tank
Question 18.
Match the items in Column ‘A’ and Column ‘B’ and choose correct answer.
| Column I | Column II |
| (i) Lady bird beetle | (a) Methano bacterium |
| (ii) Mycorrhiza | (b) Trichoderma |
| (iii) Biological control | (c) Aphids |
| (iv) Biogas | (d) Glomus |
Choose the correct match:
(a) i-b, ii-d, iii-c, iv-a
(b) i-c, ii-d, iii-b, iv-a
(c) i-d, ii-a, iii-b, iv-c
(d) i-c, ii-b, iii-a, iv-d.
Answer
Answer: (b) i-c, ii-d, iii-b, iv-a
Assertion and Reason Type Questions
These questions consist of two statements each, printed as Assertion and Reason. While answering these questions you are required to choose any one of the following four responses.
(a) If both Assertion and Reason are true and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion.
(c) If Assertion is true but the Reason is false.
(d) If both Assertion and Reason are false.
Question 19.
Assertion: Nitrogen-fixing bacteria of legume nodules live in O2-depleted cells.
Reason: Leghaemoglobin completely removes O2 from the nodule cells.
Answer
Answer: (c) If Assertion is true but the Reason is false.
Question 20.
Assertion: Nitrogen-fixing enzyme in legume root nodules functions at low oxygen concentration.
Reason: Low oxygen concentration is provided by leghaemoglobin.
Answer
Answer: (a) If both Assertion and Reason are true and the Reason is a correct explanation of the Assertion.
Question 21.
Assertion: Organochlorine pesticides are organic compounds that have been chlorinated.
Reason: Fenitrothion is one of the organochlorine pesticides.
Answer
Answer: (c) If Assertion is true but the Reason is false.
Question 22.
Assertion: Insulin is a type of antibiotic.
Reason: Insulin is synthesised by microbes by the process of fermentation.
Answer
Answer: (d) If both Assertion and Reason are false.
Question 23.
Assertion: Only Lactobacillus lactis causes curdling of milk.
Reason: Only these bacteria can produce lactic acid.
Answer
Answer: (d) If both Assertion and Reason are false.
Question 24.
Assertion: Anabaena is commonly called a symbiotic biofertiliser.
Reason: Anabaena is found as endosymbiont in the thallus of Anthoceros.
Answer
Answer: (c) If Assertion is true but the Reason is false.
Question 25.
Assertion: Discovery of penicillin by Alexander Fleming was a serendipity.
Reason: Fleming was working on Penicillium notatum along with Staphylococcus bacteria.
Answer
Answer: (c) If Assertion is true but the Reason is false.
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