MCQs For NCERT Class 12 Biology Chapter 10 Microbes in Human Welfare

Please refer to the MCQ Questions for Class 12 Biology Chapter 10 Microbes in Human Welfare with Answers. The following Microbes in Human Welfare Class 12 Biology MCQ Questions has been designed based on the latest syllabus and examination pattern for Class 12. Our experts have designed MCQ Questions for Class 12 Biology with Answers for all chapters in your NCERT Class 12 Biology book.

Microbes in Human Welfare Class 12 MCQ Questions with Answers

See below Microbes in Human Welfare Class 12 Biology MCQ Questions, solve the questions and compare your answers with the solutions provided below. 

Question. During the formation of bread it becomes porous due to release of CO₂ by the action of
(a) yeast
(b) bacteria
(c) virus
(d) protozoans.

Question. In cheese manufacture, the microorganisms are important for
(a) the ripening only
(b) the souring of milk only
(c) the development of resistance to spoilage only
(d) both the souring and the ripening processes

Question. Which of the following is a commercial blood cholesterol lowering agent?
(a) Lipases
(b) Cyclosporin A
(c) Statin
(d) Streptokinase

Question. Which of the following is correctly matched for the product produced by them?
(a) Methanobacterium : Lactic acid
(b) Penicillium notatum : Acetic acid
(c) Sacchromyces cerevisiae : Ethanol
(d) Acetobacter aceti : Antibiotics

Question. A good producer of citric acid is
(a) Clostridium
(b) Saccharomyces
(c) Aspergillus
(d) Pseudomonas.

Question. Conversion of milk to curd improves its nutritional value by increasing the amount of
(a) vitamin D
(b) vitamin A
(c) vitamin B₁₂
(d) vitamin E.

Question. Dough kept overnight in warm weather becomes soft and spongy because of
(a) absorption of carbon dioxide from atmosphere
(b) fermentation
(c) cohesion
(d) osmosis. 

Question. The most common substrate used in distilleries for the production of ethanol is
(a) corn meal
(b) soya meal
(c) ground gram
(d) molasses. 

Question. Ethanol is commercially produced through a particular species of
(a) Saccharomyces
(b) Clostridium
(c) Trichoderma
(d) Aspergillus. 

Question. Continuous addition of sugars in ‘fed batch’ fermentation is done to
(a) produce methane
(b) obtain antibiotics
(c) purify enzymes
(d) degrade sewage

Question. Which one of the following is a wrong matching of a microbe and its industrial product, while the remaining three are correct?
(a) Yeast – Statins
(b) Acetobacter aceti – Acetic acid
(c) Clostridium butylicum – Lactic acid
(d) Aspergillus niger – Citric acid 

Question. Which one of the following pairs is wrongly matched?
(a) Alcohol – Nitrogenase
(b) Fruit juice – Pectinase
(c) Textile – Amylase
(d) Detergents – Lipase

Question. Monascus purpureus is a yeast used commercially in the production of
(a) ethanol
(b) streptokinase for removing clots from the blood vessels
(c) citric acid
(d) blood cholesterol lowering statins.

Question. A patient brought to a hospital with myocardial infarction is normally immediately given
(a) penicillin
(b) streptokinase
(c) cyclosporin-A
(d) statins.

Question. Yeast (Saccharomyces cerevisiae) is used in the industrial production of
(a) tetracyline
(b) ethanol
(c) butanol
(d) citric acid.

Question. Which of the following microorganisms is used for production of citric acid in industries?
(a) Aspergillus niger
(b) Rhizopus nigricans
(c) Lactobacillus bulgaris
(d) Penicillium citrinum 

Question. Which of the following is the false statement about antibiotics?
(a) Some persons have allergy from antibiotics.
(b) Antibiotics are capable of curing any disease.
(c) This term was given by Waksman in 1942.
(d) Antibiotics is produced by microorganisms.

Question. Probiotics are
(a) cancer inducing microbes
(b) new kind of food allergens
(c) live microbial food supplement
(d) safe antibiotics. 

Question. Which of the following is used to manufacture ethanol from starch?
(a) Penicillium
(b) Saccharomyces
(c) Azotobacter
(d) Lactobacillus 

Question. The citric acid is produced by
(a) Candida utilis
(b) Azotobacter suboxydans
(c) Aspergillus niger
(d) Streptococcus lactis.

Question. The organism, used for alcohol fermentation, is
(a) Aspergillus
(b) Saccharomyces
(c) Pseudomonas
(d) Penicillium.

Question. Which of the following in sewage treatment removes suspended solids?
(a) Secondary treatment
(b) Primary treatment
(c) Sludge treatment
(d) Tertiary treatment

Question. What gases are produced in anaerobic sludge digesters?
(a) Methane and CO₂ only
(b) Methane, Hydrogen sulphide and CO₂
(c) Methane, Hydrogen sulphide and O₂
(d) Hydrogen sulphide and CO₂

Question. Secondary sewage treatment is mainly a
(a) physical process
(b) mechanical process
(c) chemical process
(d) biological process.

Question. Which of the following is mainly produced by the activity of anaerobic bacteria on sewage?
(a) Laughing gas
(b) Propane
(c) Mustard gas
(d) Marsh gas

Question. The guts of cow and buffalo possess
(a) methanogens
(b) cyanobacteria
(c) Fucus sp.
(d) Chlorella sp.

Question. The main reason why antibodies could not solve all the problems of bacteria mediated disease is
(a) decreased efficiency of the immune system
(b) insensitivity of the individual following prolonged exposure to antibiotics
(c) development of mutant strains resistant to antibodies
(d) inactivation of antibiotics by bacterial enzymes

Question. Which of the following is put into anaerobic sludge digester for further sewage treatment?
(a) Primary sludge
(b) Floating debris
(c) Effluents of primary treatment
(d) Activated sludge 

Question. In gobar gas, the maximum amount is that of
(a) butane
(b) methane
(c) propane
(d) carbon dioxide.

Question. Which one of the following pairs is wrongly matched?
(a) Yeast – Ethanol
(b) Streptomycetes – Antibiotic
(c) Coliforms – Vinegar
(d) Methanogens – Gobar gas 

Question. A major component of gobar gas is
(a) ammonia
(b) methane
(c) ethane
(d) butane. 

Question. During anaerobic digestion of organic waste, such as in producing biogas, which one of the following is left undegraded ?
(a) Lipids
(b) Lignin
(c) Hemi-cellulose
(d) Cellulose

Question. Which bacteria is utilized in gobar gas plant?
(a) Methanogens
(b) Nitrifying bacteria
(c) Ammonifying bacteria
(d) Denitrifying bacteria 

Question. Organisms called methanogens are most abundant in a
(a) sulphur rock
(b) cattle yard
(c) polluted stream
(d) hot spring. 

Question. Select the correct statement from the following.
(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

Question. Gobar gas contains mainly
(a) CO₂ + H₂
(b) CO₂ + H₂O
(c) CH₄ only
(d) CH₄ + CO₂.

Question. Which of the following can be used as a biocontrol agent in the treatment of plant disease?         
(a) Lactobacillus
(b) Trichoderma
(c) Chlorella
(d) Anabaena

Question. Microbe used for biocontrol of pest butterfly caterpillars is
(a) Saccharomyces cerevisiae
(b) Bacillus thuringiensis
(c) Streptococcus sp.
(d) Trichoderma sp.

Question. Which one of the following is an example of carrying out biological control of pests/diseases using microbes?             
(a) Trichoderma sp. against certain plant pathogens.
(b) Nucleopolyhedrovirus against white rust in Brassica.
(c) Bt-cotton to increase cotton yield.
(d) Lady bird beetle against aphids in mustard.

Question. A common biocontrol agent for the control of plant diseases is         
(a) baculovirus
(b) Bacillus thuringiensis
(c) Glomus
(d) Trichoderma. 

Question. Which of the following is not used as a biopesticide?               
(a) Trichoderma harzianum
(b) Nucleopolyhedrovirus (NPV)
(c) Xanthomonas campestris
(d) Bacillus thuringiensis 

Question. Select the correct group of biocontrol agents.   
(a) Nostoc, Azospirillium, Nucleopolyhedrovirus
(b) Bacillus thuringiensis, Tobacco mosaic virus, Aphids
(c) Trichoderma, Baculovirus, Bacillus thuringiensis
(d) Oscillatoria, Rhizobium, Trichoderma

Question. A biocontrol agent to be a part of an integrated pest management should be         
(a) species-specific and symbiotic
(b) free living and broad spectrum
(c) narrow spectrum and symbiotic
(d) species-specific and inactive on non-target organisms. 

Question. A genetically engineered microorganism used successfully in bioremediation of oil spills is a species of     
(a) Trichoderma
(b) Xanthomonas
(c) Bacillus
(d) Pseudomonas.

Question. Biological control component is central to advanced agricultural production. Which of the following is used as a third generation pesticide?             
(a) Insect repellants
(b) Organophosphate and carbamates
(c) Pathogens
(d) Pheromones 

Question. Cochineal insects have proved very useful for         
(a) cactus prevention
(b) Eichhornia prevention
(c) weeds control
(d) Parthenium control.

Question. When a natural predator (living being) is applied on the other pathogen organism to control them, this process is called           
(a) artificial control
(b) confusion technique
(c) biological control
(d) genetic engineering.

Question. The rotenone is                   
(a) a natural herbicide
(b) a natural insecticide
(c) an insect hormone
(d) a bioherbicide.

Question. Trichoderma harzianum has proved 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.

Question. Which one of the following proved effective for biological control of nematodal diseases in plants?         
(a) Gliocladium virens
(b) Paecilomyces lilacinus
(c) Pisolithus tinctorius
(d) Pseudomonas cepacia