Microbes in Human Welfare MCQs with Answers

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

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

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

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

Question-3. Antibiotics are the most effective on

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

Question-4. Bacillus thuringiensis is widely used as

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

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

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

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

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

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

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

Question-8. Methanogens do not produce

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

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

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

Question-10. Penicillin was discovered by

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

Question-11. Saccharomyces cerevisiae is used primarily for

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

Question-12. Secondary sewage tretment is mainly a

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

Question-13. Select the correct statement from the following

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

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

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

Question-15. The guts of various ruminants contain

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Question-30. Cyclosporin A is used for

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

Question-31. Glucose fermentation by yeast yields

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

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

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

Question-33. In cheese microorganisms are required for

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

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

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

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

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

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

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

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

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

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

Question-39. Saccharomyces cerevisiae is employed in production of

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

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

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

Question-41. Select the correct statement.

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

Question-42. Sewage purification is done by

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

Question-43. Statins are obtained from

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

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

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

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

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

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

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

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

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

Question-48. The domestic sewage in large cities

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

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

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

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

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

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

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

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

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

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

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

Question-54. When domestic sewage mixes with river water

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Question-69. Antibiotics are:

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

Question-70. Azoila has symbiotic relationship with:

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

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

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

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

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

Question-73. Citric acid is produced by:

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

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

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

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

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

Question-76. Nif gene occurs in:

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

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

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

Question-78. Streptomycin is produced by:

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

Question-79. Term antibiotic was first used by :

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

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

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