Below are the NEET MCQ questions on Class 12 Biology Chapter “Microbes in Human Welfare” based on the NCERT textbook. Solve the below free NEET mock test for a better understanding of the various topics. 100+ important MCQs (multiple choice questions) are given in this NEET question bank.
“Microbes in Human Welfare” is the 10th chapter in the unit “Biology in Human Welfare” of class XII or class 12th Biology NCERT. Do note that NEET (which is conducted by NTA) is based on NCERT textbooks so they are a must-have. You can also download PDFs of NCERT textbooks.
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- By fermentation, which of the following organic acid is produced?
(a) Citric acid
(b) Oxalic acid
(c) Lactic acid
(d) Propionic acid
(c) Lactic acid
- Which of these is a pair of biofertilizers?
(a) Azolla and blue-green algae
(b) Nostoc and legume
(c) Rhizobium and grasses
(d) Salmonella & E. coli
(a) Azolla and blue-green algae
- What is primary sludge used for?
(a) preparation of compost
(b) preparation of manure
(c) biogas production
(d) All of these
(d) All of these
- Which of the following is a common biocontrol agent for the control of plant diseases?
(a) Baculovirus
(b) Bacillus thuringiensis
(c) Glomus
(d) Trichoderma
(d) Trichoderma
- In organic farming, which of the following is not used?
(a) Glomus
(b) Earthworm
(c) Oscillatoria
(d) Snail
(d) Snail
- Which of the following helps plants absorb phosphorus from the soil?
(a) Glomus
(b) Rhizobium
(c) Frankia
(d) Anabaena
(a) Glomus
- Among the following, which is a wrong match between a microbe and its industrial product, while the others are correct?
(a) Yeast – statins
(b) Acetobacter aceti – acid
(c) Clostridium butylicum – lactic acid
(d) Aspergillus niger – citric acid
(c) Clostridium butylicum – lactic acid
- Rennet is purified by C. Hansen (1874) for commercial use. What is the source of this enzyme?
(a) stomach of goat
(b) stomach of horse
(c) stomach of calf
(d) bacteria
(c) stomach of calf
- Which of the following biogases is produced during sewage treatment?
(a) methane, oxygen, hydrogen sulphide
(b) hydrogen sulphide, methane, sulphur dioxide
(c) hydrogen sulphide, nitrogen, methane
(d) methane, hydrogen sulphide, carbon dioxide
(d) methane, hydrogen sulphide, carbon dioxide
- What is a good producer of citric acid?
(a) Pseudomonas
(b) Clostridium
(c) Saccharomyces
(d) Aspergillus
(d) Aspergillus
- Which microorganism is used to control pest butterfly caterpillars?
(a) Trichoderma sp.
(b) Saccharomyces cerevisiae
(c) Bacillus thuringiensis
(d) Streptococcus sp.
(c) Bacillus thuringiensis
- Anaerobic sludge digesters produce what gases?
(a) Methane and CO2 only
(b) Methane, Hydrogen Sulphide and CO2
(c) Methane, Hydrogen Sulphide and O2
(d) Hydrogen Sulphide and CO2
(b) Methane, Hydrogen Sulphide and CO2
- How is gallic acid obtained?
(a) Pseudomonas species
(b) Penicillium purpurogenum
(c) Aspergillus niger
(d) Streptomyces species
(c) Aspergillus niger
- What is IPM?
(a) International Pest Management Programme
(b) International Pesticide Management Programme
(c) Integrated Pest Management Programme
(d) Internal Pest Management Programme
(c) Integrated Pest Management Programme
- It is due to the direct action of what that sugar is converted to alcohol during fermentation?
(a) temperature
(b) micro-organisms
(c) zymase
(d) the concentration of sugar solution
(c) zymase
- Alcohol is produced by using which of the following?
(a) Bacteria
(b) Water moulds
(c) Yeasts
(d) Slime moulds
(c) Yeasts
- Some blue-green algae have the potential to be used as biofertilizers as they are?
(a) Photosynthetic
(b) Surrounded by mucilage
(c) Growing everywhere
(d) Capable of fixing nitrogen
(d) Capable of fixing nitrogen
- The enzyme that dissolves blood clots in heart attack victims is?
(a) PNA
(b) TPA
(c) NAD
(d) RFP
(b) TPA
- What do Rhizopus and Saccharomyces cerevisiae yield, respectively?
(a) invertase and lipase
(b) lipase and lipase
(c) lipase and invertase
(d) invertase and invertase
(c) lipase and invertase
- What is torulopsis utilis?
(a) food yeast
(b) microbe used to prepare vaccines
(c) used in the synthesis of citric acid
(d) used to prepare antibiotic
(a) food yeast
- What helps in the production of Roquefort cheese?
(a) Yeast
(b) Rhizopus nigricans
(c) Aspergillus niger
(d) Penicillium roquefortii
(d) Penicillium roquefortii
- It was mainly due to the efforts of who in India that biogas production technology was developed?
(a) Indian Agricultural/ Research Institute (IARI) and Khadi and Village Industries Commission (KVIC)
(b) National Botanical Research Institute (NBR1)
(c) Indian Council of Medical Research (ICMR)
(d) Indian Council of Agricultural Research (ICAR)
(a) Indian Agricultural/ Research Institute (IARI) and Khadi and Village Industries Commission (KVIC)
- Green manure is used in crop fields and sandy soils. Which plant is used for this purpose?
(a) Dicanthium annulatum and Azalia pin nata
(b) Crotalaria juncea and Alhagi camelorum
(c) Calotropis procera and Pitylanthus niruri
(d) Saccharum munja and Lantana camara
(b) Crotalaria juncea and Alhagi camelorum
- A nitrogen-fixing bacterium that associates loosely with crop roots is?
(a) Azotobacter
(b) Bacillus polymyxa
(c) Clostridium
(d) Azospirillum
(d) Azospirillum
- What does biogas consist of?
(a) carbon monoxide, methane and hydrogen
(b) carbon dioxide, methane and hydrogen
(c) carbon monoxide, ethane and hydrogen
(d) carbon dioxide, ethane and hydrogen
(b) carbon dioxide, methane and hydrogen.
- Gobar gas is more advantageous than conventional utilization as they are?
(a) More efficient source of energy
(b) Used as good fertilizer
(c) Reduces the chances of spreading pathogens
(d) All of the above
(d) All of the above
- Which of the following is a pair of biofertilizers?
(a) Azolla and blue-green algae
(b) Nostoc and legume
(c) Rhizobium and grasses
(d) Salmonella & E. coli
(a) Azolla and blue-green algae
- Pyrethrin is a common ingredient of what?
(a) Mosquito coils
(b) Fly sprays
(c) Mosquito mats
(d) All of these
(d) All of these
- What is thurioside?
(a) Insecticide
(b) Fungicide
(c) Antibiotic
(d) Weedicide
(a) Insecticide
- Sewage is purified by
(a) microbes
(b) fertilizers
(c) antibiotics
(d) antiseptics
(a) microbes
- Petro-crops are plants
(a) Grown near oil plants
(b) Used in refining crude oil
(c) Whose fossil remains formed crude oil
(d) From which petrol like fuels can be derived
(d) From which petrol like fuels can be derived
- Alexander Flemming discovered which antibiotic?
(a) Streptomycin
(b) Tetracycline
(c) Penicillin
(d) Terramycin
(c) Penicillin
- If oxygen availability to activated sludge flocs were reduced, what would happen?
(a) It will slow down the rate of degradation of organic matter.
(b) The centre of flocs will become anoxic, which would cause the 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 centre of flocs will become anoxic, which would cause the death of bacteria and eventually breakage of flocs.
- Bacterioviruses are wonderful candidates for?
(a) species-specific narrow-spectrum pesticidal applications
(b) species-specific broad-spectrum pesticidal applications
(c) species-specific narrow spectrum insecticidal applications
(d) species-specific broad-spectrum insecticidal applications
(c) species-specific narrow spectrum insecticidal applications.
- Which primitive prokaryotes produce biogas from the dung of ruminant animals?
(a) Halophiles
(b) Thermoacidiophiles
(c) Methanogens
(d) Eubacteria
(c) Methanogens
- What bacterial group is exploited in the production of biogas?
(a) Methogens
(b) Methanotrophs
(c) Organotrophs
(d) Eubacteria
(a) Methogens
- What is the methanol content of biogas?
(a) 24.6%
(b) 55.8%
(c) 8%
(d) 4%
(b) 55.8%
- What is a free-living nitrogen-fixing cyanobacterium that forms a symbiotic association with the water fern Azolla?
(a) Anabaena
(b) Tolypothrix
(c) Chlorella
(d) Nostoc
(a) Anabaena
- Which pair is correctly matched?
(a) Rhizobium – Parasite in the roots of leguminous plants
(b) Mycorrhizae – Mineral uptake from the soil
(c) Yeast – Production of biogas
(d) Myxomycetes – The ringworm diseases
(b) Mycorrhizae – Mineral uptake from the soil
- Pseudomonas is useful due to its ability to?
(a) transfer genes from one plant to another
(b) decompose a variety of organic compounds
(c) fix atmospheric nitrogen in the soil
(d) produce a wide variety of antibiotics
(b) decompose a variety of organic compounds
- What produces chloramphenicol and erythromycin (broad-spectrum antibiotics)?
(a) Streptomyces
(b) Nitrobacter
(c) Rhizobium
(d) Penicillium
(a) Streptomyces
- What is normally given to a patient with myocardial infarction when they arrive at the hospital?
(a) Penicillin
(b) Streptokinase
(c) Cyclosporin-A
(d) Statins
(b) Streptokinase
- What are microbes used for?
- primary treatment of sewage
- secondary treatment of sewage
- anaerobic sludge digester
- production of bioactive molecules
(a) 1, 3 and 4
(b) 1, 2, 3 and 4
(c) 2, 3 and 4
(d) 3 and 4
(c) 2, 3 and 4
- Which of the following statements about antibiotics is false?
(a) The first antibiotic was discovered by Alexander Flemming
(b) The term ‘antibiotic’ was coined by S. Waksman in 1942
(c) Some persons can be allergic to a particular antibiotic
(d) Each antibiotic is effective only against one particular kind of germ
(d) Each antibiotic is effective only against one particular kind of germ
- Why does penicillin inhibit bacterial multiplication?
(a) as it checks RNA synthesis
(b) as it checks DNA synthesis
(c) as it destroys chromatin formation
(d) as it inhibits cell wall formation
(d) as it inhibits cell wall formation
- How can animal excreta and organic waste from the kitchen be most profitably minimized?
(a) storing them in underground storage tanks
(b) using them for producing biogas
(c) vermiculture
(d) using them directly as biofertilizers
(b) using them for producing biogas
- Organic farming is the practice of raising crops using?
(a) Manures
(b) Resistant varieties
(c) Bio fertilisers
(d) All of these
(d) All of these
- What does Brewer’s yeast lack?
(a) diastase and amylase
(b) amylase only
(c) diastase only
(d) maltose
(a) diastase and amylase
- Bagasse is associated with the manufacture of what?
(a) cinchonidine
(b) cellulose materials
(c) resin
(d) cane sugar
(b) cellulose materials
- What bacteria are used to make butanol and acetone from starch?
(a) Lactobacillus bulgaricus
(b) Clostridium acetobutylicum
(c) Streptococcus thermophilus
(d) Both (a) and (c)
(b) Clostridium acetobutylicum
- Which bacterium contributes to the production of Swiss cheese?
(a) Propionibacterium sharmanii
(b) Trichoderma polysporum
(c) Saccharomyces cerevisiae
(d) Aspergillus niger
(a) Propionibacterium sharmanii
- Statins, a bioactive molecule, inhibit an enzyme responsible for the synthesis of?
(a) carbohydrate
(b) protein
(c) vitamins
(d) cholesterol
(d) cholesterol
- Who initiated the Ganga and Yamuna action plan?
(a) Ministry of environment and forest
(b) Ministry of agriculture
(c) Ministry of wildlife conservation
(d) None of these
(a) Ministry of environment and forest
- Citric acid is produced in industries by which of the following microorganisms?
(a) Lactobacillus bulgaricus
(b) Penicillium citrinum
(c) Aspergillus niger
(d) Rhizopus nigricans
(c) Aspergillus niger
- Azolla enriches rice fields with nitrogen because of its association with?
(a) Anabaena
(b) Nostoc
(c) Rhizobium
(d) Frankia
(a) Anabaena
- What is Yeast Saccharomyces cerevisiae used for in industrial production?
(a) butanol
(b) citric acid
(c) tetracycline
(d) ethanol
(d) ethanol
- How are microorganisms used in cheese manufacturing?
(a) the souring of milk only
(b) the ripening only
(c) development of resistance to spoilage
(d) Both (a) and (b)
(d) Both (a) and (b)
- The most abundant prokaryotes useful to humans for making curd from milk and producing antibiotics are categorised as?
(a) Cyanobacteria
(b) Archaebacteria
(c) Chemosynthetic autotrophs
(d) Heterotrophic bacteria
(d) Heterotrophic bacteria
- Which of the following microbes forms a symbiotic relationship with plants and assists them with their nutritional needs?
(a) Azotobacter
(b) Aspergillus
(c) Glomus
(d) Trichoderma
(c) Glomus
- Which pairs are correctly matched?
Column-I Column-II
A. Cyanobacteria 1. Biopesticides
B. Mycorrhiza 2. Solubilization of phosphate
C. Bacillus thuringiensis 3. Cry protein
D. Single-cell protein. 4. Rhizobia
(a) A and 2
(b) C and 3
(c) C and 4
(d) A and 3
(b) C and 3
- What happens if a wheat field is inoculated with Rhizobium?
(a) Soil will become nitrogen-rich
(b) No effect on soil nitrogen
(c) Soil will be depleted of nitrogen
(d) Soil will become rich in calcium
(b) No effect on soil nitrogen
- Select the right combination
Column-I Column-II
A. Escherichia coli I. Nif gene
B. Rhizobium melilotae II. Digestive hydrocarbon of crude oil
C. Bacillus thuringiensis III. Production of human insulin
D. Pseudomonas putida IV. Biological control of fungal disease
V. Biodecomposed insecticide
(a) A – III; B – I; C – V; D – IV
(b) A – I; B – II; C – III; D – IV
(c) A – II; B – I; C – III; D – IV
(d) A – III; B – I; C – V; D – II
(d) A – III; B – I; C – V; D – II
- What is the major source of liquid hydrocarbon?
(a) Calotropis gigantea
(b) Cocos nucifera
(c) Euphorbia antisyphilitica
(d) Solanum tuberosum
(c) Euphorbia antisyphilitica
- What does biogas consist of?
(a) CO + H2 + CO2
(b) CH4 + CO + CO2
(c) CH4 + COz + H2
(d) CO + CO2 + NO2
(c) CH4 + COz + H2
- A good substitute for diesel oil is sap from which plant?
(a) Euphorbia sp
(b) Copaifera longsdorfii
(c) Calotropis procera
(d) Manihot glaziovii
(b) Copaifera longsdorfii
- In our country, besides dung, which weed is recommended for extensive use in biogas production?
(a) Mangifera indica
(b) Hydrilla
(c) Eicchomia crassipes
(d) Solanum
(c) Eicchomia crassipes
- What is an aquatic fern that is also an excellent biofertilizer?
(a) Azolla
(b) Salvinia
(c) Marsilia
(d) Pteridium
(a) Azolla
- In paddy fields, what is a common nitrogen fixer?
(a) Rhizobium
(b) Azospirillum
(c) Oscillatoria
(d) Frankia
(b) Azospirillum
- Which organism is used as a biofertilizer for raising soybean crops?
(a) Azotobacter
(b) Azospirillum
(c) Rhizobium
(d) Nostoc
(c) Rhizobium
- In sewage treatment, which of the following removes suspended solids?
(a) Secondary treatment
(b) Primary treatment
(c) Sludge treatment
(d) Tertiary treatment
(b) Primary treatment
- Which two microbes are found to be very useful in genetic engineering?
(a) Vibrio cholerae and a tailed bacteriophage
(b) Diplococcus sp. and Pseudomonas sp.
(c) Crown gall bacterium and Caenorhabditis elegans
(d) Escherichia coli and Agrobacterium tumefaciens
(d) Escherichia coli and Agrobacterium tumefaciens
- Match the following list of microbes with their importance?
(A) Saccharomyces cerevisiae (i) Production of immunosuppressive agents
(B) Monascus Purpureus (ii) Ripening of Swiss cheese
(C) Trichoderma polysporum (iii) Commercial production of ethanol
(D) Propionibacterium sheramanii (iv) Production of blood cholesterol lowering agents
(A) (B) (C) (D)
(a) (iv) (iii) (ii) (i)
(b) (iv) (ii) (i) (iii)
(c) (iii) (i) (iv) (ii)
(d) (iii) (iv) (i) (ii)
(d) (iii) (iv) (i) (ii)
- What do the guts of cows and buffalos possess?
(a) Chlorella spp.
(b) Methanogens
(c) Cyanobacteria
(d) Fucus spp
(b) Methanogens
- Based on the product they produce, which of the following is correctly matched?
(a) Methanobacterium : Lactic acid
(b) Penicillium notatum : Acetic acid
(c) Saccharomyces cerevisiae : Ethanol
(d) Acetobacter aceti : Antibiotics
(c) Saccharomyces cerevisiae : Ethanol
- Wastewater is treated primarily by removing?
(a) dissolved impurities
(b) stable particles
(c) toxic substances
(d) harmful bacteria
(b) stable particles
- Wastewater BOD is estimated by measuring the amount of?
(a) total organic matter
(b) biodegradable organic matter
(c) oxygen evolution
(d) oxygen consumption
(d) oxygen consumption
- Among the following alcoholic beverages, which one is produced without distillation?
(a) Wine
(b) Whisky
(c) Rum
(d) Brandy
(a) Wine
- Which pair is incorrectly matched?
(a) Yeast – ethanol
(b) Streptomycetes – antibiotic
(c) Coliforms – vinegar
(d) Methanogens – gobar gas
(c) Coliforms – vinegar
- What has Trichoderma harzianum proved to be useful for?
(a) bioremediation of contaminated soils
(b) reclamation of wastelands
(c) gene transfer in higher plants
(d) biological control of soil-borne plant pathogens
(d) biological control of soil-borne plant pathogens
- Which of the following statements is true about BOD?
(a) The greater the BOD of wastewater, the more is its polluting potential
(b) The greater the BOD of wastewater, the less is its polluting potential
(c) The lesser the BOD of wastewater, the more is its polluting potential
(d) The lesser the BOD of wastewater, the less is its polluting potential
(a) The greater the BOD of wastewater, the more is its polluting potential
- What is the use of the free-living fungus Trichoderma?
(a) killing insects
(b) biological control of plant diseases
(c) controlling butterfly caterpillars
(d) producing antibiotics
(b) biological control of plant diseases
- Where does vitamin B2 come from?
(a) Penicillium
(b) Acetobacter
(c) Aspergillus
(d) Ashbya gossypii
(d) Ashbya gossypii
- Read the following statement having two blanks (A and B):
Drugs for patients diagnosed with (A) are derived from a species of (B).
Which is the one correct option for the two blanks?
Blank – A Blank – B
(a) Heart Penicillium
(b) Organ-transplant Trichoderma
(c) Swine flu Monascus
(d) AIDS Pseudomonas
(b) Organ-transplant Trichoderma
- Which bacteria help in nitrogen fixation in the atmosphere?
1 Azotobacter
2 Rhizobium
3 Azospirillum
4 Lactobacillus
(a) 1, 3 and 4
(b) 1, 2, 3 and 4
(c) 2, 3 and 4
(d) 1, 2 and 3
(d) 1, 2 and 3
- What do methanogens that grow anaerobically, produce on cellulose?
- methane
- oxygen
- carbon dioxide
- hydrogen
(a) 1, 3 and 4
(b) 1, 2, 3 and 4
(c) 2, 3 and 4
(d) 1 and 2
(a) 1, 3 and 4
- What vitamin increases in content as milk is converted into curd by lactic acid bacteria?
(a) vitamin-C
(b) Vitamin-D
(c) vitamin-B12
(d) vitamin-E
(c) vitamin-B12
- Sludge generated during wastewater treatment can be treated by?
(a) anaerobic digesters
(b) activated sludge
(c) chemicals
(d) oxidation pond
(a) anaerobic digesters
- Where are methanogenic bacteria not found?
(a) rumen of cattle
(b) gobar gas plant
(c) bottom of water-logged paddy fields
(d) activated sludge
(d) activated sludge
- Match the following column of bacteria with their commercially important products
Column I Column II
(Bacterium) (Product)
A. Aspergillus niger 1. Lactic acid
B. Acetobacter aceti 2. Butyric acid
C. Clostridium butylicum 3. Acetic acid
D. Lactobacillus 4. Citric acid A B C D
(a) 2 3 4 1
(b) 2 4 3 1
(c) 4 3 2 1
(d) 4 1 3 2
(c) 4 3 2 1
- Match the following column of bioactive substances and their roles.
Column I Column II
(Bioactive Substance) (Role)
A. Statin 1. Removal of oil stains
B. Cyclosporin A 2. Removal of clots from blood vessels
C. Streptokinase 3. Lowering of blood cholesterol
D. Lipase 4. Immuno-suppressive agent
Choose the correct match
A B C D
(a) 2 3 1 4
(b) 4 2 1 3
(c) 4 1 3 2
(d) 1 2 3 4
(d) 1 2 3 4
- India developed the technology of producing biogas from cow dung largely due to the efforts of?
(a) Gas Authority of India
(b) Oil and Natural Gas Commission
(c) India Agricultural Research Institute, Khadi and Village Industries Commission
(d) Indian Oil Corporation
(c) India Agricultural Research Institute, Khadi and Village Industries Commission
- Mycorrhizae do not help the host plant in what?
(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
- Which of the following organisms cannot fix nitrogen?
(a) Anabaena
(b) Nostoc
(c) Azotobacter
(d) Pseudomonas
(d) Pseudomonas
- What makes the big holes in Swiss cheese?
(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
- Residue left after methane production from cattle dung is?
(a) burnt
(b) buried in landfills
(c) used as manure
(d) used in civil construction
(c) used as manure
- What do methanogens not produce?
(a) oxygen
(b) methane
(c) hydrogen sulphide
(d) carbon dioxide
(a) oxygen
- Activated sludge should settle quickly so that it can?
(a) be rapidly pumped back from the sedimentation tank to the aeration tank
(b) absorb pathogenic bacteria present in wastewater 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 the sedimentation tank to the aeration tank
- Match the columns below
Column I Column II
A. Ladybird 1. Methanobacterium
B. Mycorrhiza 2. Trichoderma
C. Biological control 3. Aphids
D. Biogas 4. Glomus A B C D
(a) 2 4 3 1
(b) 3 4 2 1
(c) 4 1 2 3
(d) 3 2 1 4
(b) 3 4 2 1
- A transgenic species of what is being used to produce human insulin?
(a) Escherichia
(b) Mycobacterium
(c) Rhizobium
(d) Saccharomyces
(a) Escherichia
- Cryl endotoxins obtained from Bacillus thuringiensis are effective against which organisms?
(a) mosquitoes
(b) flies
(c) nematodes
(d) bollworms
(d) bollworms
Goodluck Medicoholics! Until next time.