Microbes in Human Welfare MCQs with Answers

Question-1. ____________ is a pigment that gives a pinkish hue to rhizobium induced root nodules

1. None of these
2. Leghaemoglobin
3. Carotenoid
4. Mauveine

Question-2. Activated sludge should have the ability to settle quickly so that it can

1. absorb colloidal organic matter.
2. be rapidly pumped back from sedimentation tank to aeration tank
3. absorb pathogenic bacteria present in waste water while sinking to the bottom of the settling tank
4. be discarded and anaerobically digested

Question-3. Antibiotics are the most effective on

1. None of the these
2. Bacteria
3. Virus
4. Fungi

Question-4. Bacillus thuringiensis is widely used as

1. None of these
2. Insecticide
3. Weedicides
4. Rodenticide

Question-5. Big holes in Swiss cheese are made by a

1. a machine
2. a bacterium producing a large amount of carbon dioxide
3. a fungus that releases a lot of gases during its metabolic activities
4. a bacterium that produces methane gas

Question-6. BOD of waste water is estimated by measuring the amount of

1. total organic matter
2. oxygen consumption
3. oxygen evolution
4. biodegradable organic matter

Question-7. High biological oxygen demand in a water body means

1. None of these
2. Water is polluted
3. Water is not polluted
4. Waterbody contains lots of lifeforms

Question-8. Methanogens do not produce

1. carbon dioxide
2. oxygen
3. methane
4. hydrogen sulfide

Question-9. Mycorrhiza does not help the host plant in

1. Enhancing its phosphorus uptake capacity
2. Increasing its resistance to insects
3. Enhancing its resistance to root pathogens
4. Increasing its tolerance to drought

Question-10. Penicillin was discovered by

1. Dubois
2. Fleming
3. Waksman
4. Burkholder

Question-11. Saccharomyces cerevisiae is used primarily for

1. Biofuel
2. Baking
3. Bleaching
4. None of these

Question-12. Secondary sewage tretment is mainly a

1. Physical proces
2. Biological process
3. Chemical proces
4. Mechanical process

Question-13. Select the correct statement from the following

1. Biogas commnly called gobar gas in pure methane
2. Activated sludge sediment is dettlement tanks of sewage treatment plant is rich source of aerobic bacteria
3. Biogas is produced by the activity of aerobic bacteria on animal waste
4. None of these

Question-14. The free-living fungus Trichoderma can be used for

1. killing insects
2. biological control of plant diseases
3. controlling butterfly caterpillars
4. producing antibiotics

Question-15. The guts of various ruminants contain

1. None of these
2. Methanogens
3. Halophiles
4. Borth

Question-16. The primary treatment of waste water involves the removal of

1. dissolved impurities
2. stable particles
3. toxic substances
4. harmful bacteria

Question-17. The residue left after methane production from cattle dung is:

1. burnt
2. used as manure
3. used in civil construction
4. burried in land fills

Question-18. The technology of biogas production from cow dung was developed in India largely due to the efforts of

1. Gas Authority of India
2. Indian Agricultural Research Institute and Khadi & Village Industries Commission
3. Indian Oil Corporation
4. Oil and Natural Gas Commission

Question-19. The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is

1. vitamin C
2. vitamin B12
3. vitamin E.
4. vitamin D

Question-20. Vinegar is prepared from alcohol with the help of

1. None of these
2. Acetobacter
3. Lactobacillus
4. Acetobacter

Question-21. Wastewater treatment generates a large quantity of sludge, which can be treated by

1. activated sludge
2. oxidation pond
3. chemicals
4. digesters

Question-22. What would happen if oxygen availability to activated sludge flocs is reduced?

1. It will slow down the rate of degradation of organic matter
2. The center of flocs will become anoxic, which would cause death of bacteria and eventually breakage of flocs
3. Flocs would increase in size as anaerobic bacteria would grow around flocs
4. Protozoa would grow in large numbers

Question-23. Which of the following is mainly produced by the activity of aerobic bacteria on sewage

1. Propane
2. March gas
3. Laughing gas
4. Mustard gas

Question-24. Which of the following microbes are used for the commercial production of citric acid?

1. All of these
2. Aspergillus
3. Asparagus
4. Asparagine

Question-25. Which of these processes does not give off CO2?

1. None of these
2. Lactate fermentation
3. Aerobic respiration
4. Alcoholic fermentation

Question-26. Which one of the following alcoholic drinks is produced without distillation?

1. Brandy
2. Wine
3. Whisky
4. Rum

Question-27. Which one of the following is not a nitrogen-fixing organism?

1. Anabaena
2. Pseudomonas
3. Azotobacter
4. Nostoc

Question-28. A biocontrol agent to be a part of an integrated pest management should be

1. species-specific and inactive on non-target organisms.
2. species-specific and symbiotic
3. free living and broad spectrum
4. narrow spectrum and symbiotic

Question-29. Conversion of sugar into alcohol during fermentation is due to the direct action of

1. concentration of sugar solution
2. temperature
3. micro-organisms
4. zymase

Question-30. Cyclosporin A is used for

1. enhancing tenderness of meat
2. dissolving blood clots
3. lowering cholesterol level
4. immunosuppression

Question-31. Glucose fermentation by yeast yields

1. H2O + CO2
2. ethanol + CO2
3. ethanol + H2O
4. methanol + CO2

Question-32. In biogas plant, the role of acidogenic bacteria is to

1. digest fungi in the sludge.
2. convert monomers to organic acids
3. convert monomers to complex polymers
4. transform acetic acid to biogas

Question-33. In cheese microorganisms are required for

1. development of resistance to spoilage
2. ripening only
3. souring of milk only
4. souring and ripening

Question-34. In gobar gas, the maximum amount is that of

1. carbon dioxide.
2. butane
3. methane
4. propane

Question-35. Lactic acid bacteria convert milk into curd and improves its nutritional quality by enhancing

1. vitamin D
2. vitamin A
3. vitamin B
4. vitamin C

Question-36. Monascus purpureus is a yeast used commercially in the production of

1. blood cholesterol lowering statins
2. ethanol
3. streptokinase for removing clots from the blood vessels
4. citric acid

Question-37. Recently Govt. of India has allowed mixing of alcohol in petrol. What is the amount of alcohol permitted for mixing in petrol?

1. 5%
2. 2.50%
3. 10-15%
4. 10%

Question-38. Refer to the given diagram and choose the correct option for it.

1. Prion - AlzheimerÂ’s disease
2. Bacteriophage - Tobacco mosaic disease
3. Adenovirus - Respiratory disease
4. Viroid - Potato spindle tumour disease

Question-39. Saccharomyces cerevisiae is employed in production of

1. all of these
2. idli
3. beer
4. bread

Question-40. Select the correct group of biocontrol agents.

1. Oscillatoria, Rhizobium, Trichoderma
2. Nostoc, Azospirillum, Nucleopolyhedrovirus
3. Bacillus thuringiensis, Tobacco mosaic virus, Aphids
4. Trichoderma, Baculovirus, Bacillus thuringiensis

Question-41. Select the correct statement.

1. Methanogens are found in aerobic conditions.
2. Acetobacter aceti produces citric acid.
3. Saccharomyces cerevisiae is used as clot buster.
4. Penicillium notatum restrict the growth of Staphylococci.

Question-42. Sewage purification is done by

1. antiseptics
2. microbes
3. fertilizers
4. antibiotics

Question-43. Statins are obtained from

1. Clostridium butyricum
2. Streptococcus
3. Mucor javanicus
4. Monascus purpureus

Question-44. Statins, a bioactive molecule, inhibits the enzyme responsible for synthesis of

1. cholesterol
2. carbohydrate
3. protein
4. vitamins

Question-45. Streptokinase, used as a ‘clot buster’ is obtained from

1. Saccharomyces
2. Streptococcus
3. Staphylococcus
4. Lactobacillus

Question-46. The bacterium that commonly lives in animal and human intestine is

1. Corynebacterium
2. Bacillus anthracis
3. Vibrio cholerae
4. Escherichia coli

Question-47. The bioactive molecule cyclosporin A is used in the treatment of

1. organ-transplant patients
2. whooping cough
3. diphtheria
4. leprosy

Question-48. The domestic sewage in large cities

1. has very high amount of suspended solids and dissolved salts.
2. has a high BOD as it contains both aerobic and anaerobic bacteria
3. is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs)
4. when treated in STPs does not really require the aeration step as the sewage contains adequate oxygen

Question-49. The given figure represents a typical biogas plant. Select the correct option for A, B and C respectively.(image) 31

1. All of these
2. A is the inlet for cattle dung.
3. C is the outlet for the release of biogas.
4. B is the chamber which contains leftover slurry.

Question-50. The guts of cow and buffalo possess:

1. Fucus spp.
2. Chlorella spp
3. Methanogens
4. Cyanobacteria

Question-51. The large vessels for growing microbes on an industrial scale are called _________ .

1. fermentors
2. petridish
3. digestors
4. biogas vessel

Question-52. The microbial biocontrol agent for butterfly caterpillar is

1. Cyanobacteria
2. Bacillus thuringiensis
3. Saccharomyces
4. Lactobacillus

Question-53. What gases are produced in anaerobic sludge digesters?

1. Hydrogen sulphide and CO2
2. Methane and CO2 only
3. Methane, Hydrogen sulphide and CO2
4. Methane, Hydrogen sulphide and O2

Question-54. When domestic sewage mixes with river water

1. the river water is still suitable for drinking as impurities are only about 0.1%.
2. small animals like rats will die after drinking river water
3. the increased microbial activity releases micronutrients such as iron
4. the increased microbial activity uses up dissolved oxygen

Question-55. Which bacterium helps in the production of Swiss cheese?

1. Aspergillus niger
2. Propionibacterium sharmanii
3. Trichoderma polysporum
4. Saccharomyces cerevisiae

Question-56. Which gas is responsible for the puffed-up appearance of dough ?

1. NO2
2. CO2
3. O2
4. SO2

Question-57. Which of the following bacteria converts milk into curd ?

1. Bacillus
2. Propionibacterium
3. Lactobacillus
4. Streptococcus

Question-58. Which of the following can be used as a biocontrol agent in the treatment of plant disease?

1. Anabaena
2. Lactobacillus
3. Trichoderma
4. Chlorella

Question-59. Which of the following in sewage treatment removes suspended solids?

1. Tertiary treatment
2. Secondary treatment
3. Primary treatment
4. Sludge treatment

Question-60. Which of the following is correctly matched for the product produced by them?

1. Acetobacter aceti : Antibiotics
2. Methanobacterium : Lactic acid
3. Penicillium notatum : Acetic acid
4. Saccharomyces cerevisiae : Ethanol

Question-61. Which of the following scientists showed that Saccharomyces cerevisiae causes fermentation forming products such as beer and buttermilk ?

1. Schatz
2. Louis Pasteur
3. Alexander Flemming
4. Selman Waksman

Question-62. Which one of the following is not used in organic farming?

1. Snail
2. Glomus
3. Earthworm
4. Oscillatoria

Question-63. Which one of the following is used in the manufacture of alcohol ?

1. Slime molds
2. Bacteria
3. Bread molds
4. Yeastsans

Question-64. Which one of the following pair is wrongly matched?

1. Coliforms — Vinegar
2. Methanogens — Gobar gas
3. Yeast — Ethanol
4. Streptomycetes — Antibiotic

Question-65. Which role is played by lactic acid bacteria (LAB) in our stomach ?

1. All of these
2. Beneficial
3. Harmful
4. Neutral

Question-66. Yeast (Saccharomyces cerevisiae) is used in the industrial production of

1. ethanol
2. butanal
3. citric acid
4. tetracyclin

Question-67. A free living anaerobic nitrogen fixing bacterium is:

1. Clostridium
2. Rhizobium
3. Streptococcus
4. Azotobactor

Question-68. A free-living aerobic and non-photosynthetic nitrogen fixing bacterium is:

1. Rhizobium
2. Anabaena
3. Clostridium
4. Azotobactor

Question-69. Antibiotics are:

1. Syrups
2. Medicines
3. Toxin
4. Plants

Question-70. Azoila has symbiotic relationship with:

1. Tolypothrix
2. Chlotfila
3. Anabaena
4. Nostoc

Question-71. Bacillus thuringiensis (Bt) strains have been used for designing novel:

1. Bio-fertilizers
2. Bio-metallurigcal techniques
3. Bio-mineralization process
4. Bio-insecticidal plants

Question-72. By anobacteria are useful biofertilizers in the; field of:

1. Sugarcane
2. Wheat
3. Maize
4. Rice

Question-73. Citric acid is produced by:

1. Saccharomyces
2. Rhizopus
3. Mucor
4. Aspergillus

Question-74. For retting of jute, the fermenting microbe is:

1. Streptococcus lactin
2. Methanophilic bacteria
3. Butyric acid bacteria
4. Helicobactor pylon

Question-75. In nostoc, enzyme nitrogenase occurs in :

1. Only in hormogones
2. Vegetative cells
3. Heterocysts
4. Both (a) and (b)

Question-76. Nif gene occurs in:

1. Streptococcus
2. Peiiicillium
3. Rhizobium
4. Aspergillus

Question-77. Streptococcus is used in the preparation of:

1. Bread
2. Wine
3. Idli
4. Paneer

Question-78. Streptomycin is produced by:

1. By Streptomyces griseus
2. By Streptomyces Scoleus
3. By Streptomyces fradiae
4. By Streptomyces venezueleae

Question-79. Term antibiotic was first used by :

1. Lister
2. Flemming
3. Pasteur
4. Waksman

Question-80. Usnic acid is an antibiotic obtained from :

1. Algae
2. Fungi
3. Bacteria
4. Lichens