Free PDF Download of CBSE Biology Multiple Choice Questions for Class 12 with Answers Chapter 10 Microbes in Human Welfare. Biology MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 12 Biology Microbes in Human Welfare MCQs Pdf with Answers to know their preparation level.
Microbes in Human Welfare Class 12 Biology MCQs Pdf
Question 1.
A nitrogen fixing microbe associated with the fern Azolla in rice fields is
(a) Frankia
(b) Rhizobium
(c) Spirulina
(d) Anabaena
Answer:
(d) Anabaena
Question 2.
Azolla pinnata has been found to be an important biofertiliser for paddy crops. This quality is due to the presence of
(a) N2 fixing bacteria
(b) N2 fixing cyanobacteria
(c) mycorrhizae
(d) all of these
Answer:
(b) N2 fixing cyanobacteria
Question 3.
Which of the following is widely used as a successful biofertiliser in Indian rice field ?
(a) Rhizobium
(b) Acacia arabica
(c) Acalypha indica
(d) Azolla pinnata
Answer:
(d) Azolla pinnata
Question 4.
Which of the following options incldes biofertilscrs ?
(a) cowdung manure and farmyard waste
(b) A quick growing crop ploughed back into the field
(c) Nostoc, Oscillatoria
(d) All of these
Answer:
(c) Nostoc, Oscillatoria
Question 5.
Which of the following is a non-symbiotic biofertiliser ?
(a) VAM
(b) Azotobacter
(c) Anabaena
(d) Rhizobium
Answer:
(b) Azotobacter
Question 6.
Nitrogen fixation in root nodules of Alnus is brought about by
(a) Frankia
(b) Azorhizobium
(c) Bradyrhizobium
(d) Clostridium
Answer:
(a) Frankia
Question 7.
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:
(c) vitamin B12
Question 8.
Wastewater treatment generates a large quantity of sludge, which can be treated by
(a) anaerobic digesters
(b) floe
(c) chemicals
(d) oxidation pond
Answer:
(a) anaerobic digesters
Question 9.
Methanogenic bacteria are not found in
(a) rumen of cattle
(b) gobar gas plant
(c) bottom of water-logged paddy field
(d) activated sludge
Answer:
(d) activated sludge
Question 10.
The primary treatment of wastewater involves the removal of
(a) dissolved impurities
(b) stable particles
(c) toxic substances
(d) harmful bacteria
Answer:
(b) stable particles
Question 11.
BOD of wastewater is estimated by measuring the amount of
(a) total organic matter
(b) biodegradable organic matter
(c) oxygen evolution
(d) oxygen consumption
Answer:
(d) oxygen consumption
Question 12.
Which one of the following alcoholic drinks is produced without distillation ?
(a) Wine
(b) Whisky
(c) Rum
(d) Brandy
Answer:
(a) Wine
Question 13.
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:
(b) biological control of plant diseases
Question 14.
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:
(d) increasing its resistance to insects
Question 15.
Which one of the following is not a nitrogen-fixing organism ?
(a) Anabaena
(b) Nostoc
(c) Azotobacter
(d) Pseudomonas
Answer:
(d) Pseudomonas
Question 16.
Which of the following microbes is a proteinacious infectious agent ?
(a) Fungi
(b) Prions
(c) Bacteria
(d) Protozoa
Answer:
(b) Prions
Question 17.
The nutritive medium for growing bacteria and many fungi in laboratory is called
(a) growth media
(b) suspension media
(c) culture media
(d) colonial media
Answer:
(c) culture media
Question 18.
The inoculum is added to the fresh milk in order to convert milk into curd, the term ‘inoculum’ here refers to
(a) a starter rich in vitami Bp
(b) a starter rich in proteins
(c) a starter containing milions of LAB
(d) an aerobic digester
Answer:
(c) a starter containing milions of LAB
Question 19.
Which of the following organisms is used in the production of beverages ?
(a) Penicillium notatum
(b) Saccharomyces cerevisiae
(c) Aspergilus niger
(d) Clostridium butylicum
Answer:
(b) Saccharomyces cerevisiae
Question 20.
Which of the following options contains the end products formed during anaerobic respiration in yeast ?
(a) H2O, CO2 and energy
(b) H2S, C6H12O6 and energy
(c) CO2, C2H5OH and energy
(d) H2O and CO2
Answer:
(c) CO2, C2H5OH and energy
Question 21.
The chemical substances produced by some microbes which can kill or retard the growth of other microbes are called
(a) antiseptics
(b) antacids
(c) antibiotics
(d) all of these
Answer:
(c) antibiotics
Question 22.
Antibiotics are obtained from
(a) bacteria
(b) fungi
(c) actinomycetes
(d) all of these
Answer:
(d) all of these
Question 23.
Which of the following antibiotics was extensively used to treat American soldiers wounded in World War 11 ?
(a) Neomycin
(b) Bacitracin
(c) Chloramphenicol
(d) Penicillin
Answer:
(d) Penicillin
Question 24.
Streptomycin is obtained from
(a) Streptomyces griseus
(b) S. cerevisiae
(c) S. venezuelae
(d) S. rimosus
Answer:
(a) Streptomyces griseus
Question 25.
Integrated Pest Management (IPM) discourages the excessive used of
(a) biological methods
(b) chemical pesticides
(c) mechanical methods
(d) all of these
Answer:
(b) chemical pesticides
Question 26.
Which of the following is not used as a biopesticide ?
(a) Trichoderma harzianum
(b) Nucleopolyhedrovirus
(c) Xanthomonas campestris
(d) Bacillus thuringiensis
Answer:
(c) Xanthomonas campestris
Question 27.
Organic farming does not include
(a) green manures
(b) chemical fertilisers
(c) farmyard manures
(d) compost
Answer:
(b) chemical fertilisers
Question 28.
Organic farming includes
(a) use of fertilisers and pesticides of biological origin
(b) IPM (Integrated Pest Management)
(c) locally developed pest resistant varieties
(d) all of these
Answer:
(d) all of these
Question 29.
Living organisms used to enrich the nutrient quality of the soil are called as
(a) biocontrol agents
(b) biofertilisers
(c) synthetic fertilisers
(d) natural fertilisers
Answer:
(d) natural fertilisers
Question 30.
Biofertilisers are
(a) some bacteria and cyanobacteria
(b) fertilisers formed by ploughing in barseem
(c) fertilisers obtained by decay of dead organisms
(d) fertilisers prepared by mixing cattle dung with crop residues
Answer:
(a) some bacteria and cyanobacteria
Question 31.
Biofertilisers are the living organisms which
(a) bring about soil nutrient enrichment
(b) maximise the ecological benefits
(c) minimise the environmental hazards
(d) all of these
Answer:
(d) all of these
Question 32.
Which one of the following can be used as biofertiliser in cotton field ?
(a) Azolla-Anabaena
(b) Streptococcus
(c) Azospirillum
(d) Azotobacter chroococcum
Answer:
(d) Azotobacter chroococcum
Question 33.
The symbiotic association between fungi and roots of higher plants is referred to as
(a) lichen
(b) mycorrhiza
(c) biofertiliser
(d) biocontrol agent
Answer:
(b) mycorrhiza
Question 34.
Cyanobacteria are
(a) heterotrophs
(b) chemotrophs
(c) autotrophs
(d) organotrophs
Answer:
(c) autotrophs
Question 35.
Enzyme which has the fibrinolytic effect is
(a) protease
(b) amylase
(c) lipase
(d) streptokinase
Answer:
(d) streptokinase
Question 36.
Statins used for lowering blood cholesterol level are extracted from
(a) algae
(b) bacteria
(c) viruses
(d) yeast
Answer:
(d) yeast
Question 37.
Monascus purpureus is a yeast commercially used in the production of
(a) citric acid
(b) ethanol
(c) blood cholesterol lowering statins
(d) streptokinase for removing clots from blood vessels
Answer:
(c) blood cholesterol lowering statins
Question 38
is the first step of sewage treatment.
(a) Precipitation
(b) Chlorination
(c) Sedimentation
(d) Aeration
Answer:
(c) Sedimentation
Question 39.
During the primary treatment of sewage, solid particles that settle down are called
(a) floes
(b) primary sludge
(c) activated sludge
(d) anaerobic sludge
Answer:
(b) primary sludge
Question 40.
The purpose of biological treatment of waste water is to
(a) reduce BOD
(b) increase BOD
(c) reduce sedimentation
(d) increase sedimentation
Answer:
(a) reduce BOD
Question 41.
The masses of bacteria held together by slime and fungal filaments to form mesh-like structures are called as
(a) primary sludge
(b) floes
(c) activated sludge
(d) anaerobic sludge
Answer:
(b) floes
Question 42.
BOD is………..in polluted water and in potable water.
(a) more, less
(b) less, more
(c) less in both
(d) medium in both
Answer:
(a) more, less
Question 43.
In the sewage treatment, bacterial floes are allowed to sediment in a settling tank. This sediment is called as
(a) inactivated sludge
(b) activated sludge
(c) primary sludge
(d) secondary sluge
Answer:
(b) activated sludge
Question 44.
Which of the following steps is taken by the Ministry of Environment and Forests to protect rivers from water pollition ?
(a) Ganga Action Plan
(b) Narmada Action Plan
(c) Yamuna Action Plan
(d) Both (a) and (c)
Answer:
(d) Both (a) and (c)
Question 45.
Methanogens, growing anaerobically on cellulosic material produce
(a) methane
(b) methane and carbon dioxide
(c) methane and hydrogen
(d) methane, carbon dioxide and hydrogen
Answer:
(d) methane, carbon dioxide and hydrogen
Question 46.
Which of the following bacteria is present in the rumen of cattle ?
(a) Azotobacter
(b) Rhizobium
(c) Methanobacterium
(d) Azospirillum
Answer:
(c) Methanobacterium
Question 47.
Process of biogas production is
(a) aerobic process
(b) anaerobic process
(c) active process
(d) passive process
Answer:
(b) anaerobic process
Question 48.
Biogas is produced by
(a) aerobic breakdown of biomass
(b) anaerobic breakdown of biomass
(c) with the help of methanogenic bacteria
(d) both (b) and (c)
Answer:
(d) both (b) and (c)
Question 49.
Dragonflies are used to get rid of
(a) mosquitoes
(b) aphids
(c) butterfly caterpillars
(d) both (a) and (b)
Answer:
(a) mosquitoes
Question 50.
A microbial biocontrol agent that can be used to control butterfly caterpillars is
(a) Trichoderma polysporum
(b) Bacillus thuringiensis
(c) Streptococcus
(d) mycorrhiza
Answer:
(b) Bacillus thuringiensis
Question 51.
Bacillus thuringiensis is used to control
(a) bacterial pathogens
(b) fungal pathogens
(c) nematodes
(d) insect pests
Answer:
(d) insect pests
Question 52.
Bacillus thuringiensis (Bt) strains have been used for designing novel
(a) biofertilisers
(b) bio-metallurgical techniques
(c) bio-mineralisation process
(d) bio-insecticidal plants
Answer:
(d) bio-insecticidal plants
Question 53.
Trichoderma harzianum has proved to be a useful microorganism for
(a) gene transfer in higher plants
(b) biological control of soil-borne plant pathogens
(c) bioremediation of contaminated soils
(d) reclamation of wastelands
Answer:
(b) biological control of soil-borne plant pathogens
Question 54.
Baculoviruses (Nucleopolyhedrovirus) do not show
(a) host specificity
(b) narrow spectrum applications
(c) effects on non-target pathogens
(d) utility in IPM programme
Answer:
(c) effects on non-target pathogens
Question 55.
The residue left after methane production from cattle dung is
(a) burnt
(b) burried in land fills
(c) used as manure
(d) used in civil construction
Answer:
(c) used as manure
Question 56.
Methanogens do not produce
(a) oxygen
(b) methane
(c) hydrogen sulphide
(d) carbon dioxide
Answer:
(a) oxygen
Question 57.
Microbes are present in
(a) soil
(b) thermal vents
(c) polluted water
(d) all of these
Answer:
(d) all of these
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