Q1. Which pair is not correctly matched?
Correct Answer: (b)
Serratia is not associated with drug addiction; the other pairs are correct.
Q2. Ethanol is commercially produced through
Correct Answer: (a)
Saccharomyces cerevisiae ferments carbohydrates to ethanol.
Q3. Modern detergents contain enzyme preparations from
Correct Answer: (b)
Alkaliphilic microbes provide enzymes that remain active in alkaline detergent solutions.
Q4. The term antibiotic was first used by
Correct Answer: (c)
Selman Waksman coined the term “antibiotic” in 1942.
Q5. Microbe used for biocontrol of pest butterfly caterpillars is
Correct Answer: (c)
Bt produces Cry proteins toxic to insect larvae, including butterfly caterpillars.
Q6. Gobar gas contains mainly
Correct Answer: (a)
Biogas is chiefly methane with carbon dioxide; oxygen and sulphur dioxide are not principal components.
Q7. Which microorganism is used for industrial citric-acid production?
Correct Answer: (b)
Aspergillus niger is the standard industrial producer of citric acid.
Q8. Which microbe forms symbiotic association with plants and helps their nutrition?
Correct Answer: (c)
Glomus forms mycorrhizae that improve mineral absorption.
Q9. In gobar gas, the maximum amount is that of
Correct Answer: (b)
Methane is the major combustible component of biogas.
Q10. Which sewage-treatment stage removes suspended solids?
Correct Answer: (b)
Primary treatment physically removes floating debris and suspended solids through filtration and sedimentation.
Q11. During sewage treatment, biogas includes
Correct Answer: (d)
Biogas is chiefly methane and CO2, with traces of hydrogen sulphide.
Q12. Bread becomes porous because CO2 is released by
Correct Answer: (a)
Yeast fermentation produces CO2 gas, which forms pores in bread.
Q13. Which is biological control of plant pests/diseases using microbes?
Correct Answer: (a)
Trichoderma species control several soil-borne plant pathogens.
Q14. Which is a non-symbiotic biofertiliser?
Correct Answer: (a)
Azotobacter is a free-living, non-symbiotic nitrogen fixer.
Q15. Which is a pair of biofertilisers?
Correct Answer: (a)
Azolla and blue-green algae enrich fields through nitrogen fixation.
Q16. Rice yield has been increased by use of
Correct Answer: (a)
Anabaena is a cyanobacterial biofertiliser that improves rice yield.
Q17. A drug used for _____ patients is obtained from _____ .
Correct Answer: (b)
Cyclosporin A from Trichoderma polysporum is an immunosuppressant used in organ transplantation.
Q18. Which is a commercial blood-cholesterol lowering agent?
Correct Answer: (b)
Statins, produced by Monascus purpureus, inhibit cholesterol synthesis and lower blood cholesterol.
Q19. Dough kept overnight becomes soft and spongy because of
Correct Answer: (b)
Yeast fermentation releases CO2, making dough soft and porous.
Q20. Select the correct statement.
Correct Answer: (d)
Activated sludge contains aerobic microbial flocs; biogas is anaerobic and methane-rich, not pure methane.
Q21. Biofertiliser for raising soybean crops is
Correct Answer: (c)
Soybean is a legume and forms nitrogen-fixing root nodules with Rhizobium.
Q22. Match microbes with their importance.
| Microbe | 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 sharmanii | (iv) Production of blood-cholesterol lowering agents |
Correct Answer: (d)
Yeast produces ethanol; Monascus produces statins; Trichoderma produces cyclosporin A; Propionibacterium ripens Swiss cheese.
Q23. Domestic sewage in large cities
Correct Answer: (b)
Sewage receives aerobic secondary treatment; activated sludge is then anaerobically digested.
Q24. Nitrogen-fixing microbe associated with Azolla in rice fields is
Correct Answer: (b)
Anabaena lives symbiotically in Azolla and fixes nitrogen.
Q25. Match organisms with products.
| Organism | Product |
|---|
| (a) Lactobacillus | (i) Cheese |
| (b) Saccharomyces cerevisiae | (ii) Curd |
| (c) Aspergillus niger | (iii) Citric acid |
| (d) Acetobacter aceti | (iv) Bread |
| (v) Acetic acid |
Select the correct combination for (a)-(d).
Correct Answer: (b)
Lactobacillus makes curd, yeast makes bread, A. niger makes citric acid and A. aceti makes acetic acid.
Q26. The aquatic fern that is an excellent biofertiliser is
Correct Answer: (a)
Azolla contains nitrogen-fixing Anabaena and is used in rice fields.
Q27. A non-photosynthetic aerobic nitrogen-fixing soil bacterium is
Correct Answer: (c)
Azotobacter is an aerobic, free-living, non-photosynthetic nitrogen fixer.
Q28. Which is not a biofertiliser?
Correct Answer: (a)
Agrobacterium is primarily a plant pathogen/vector, not a biofertiliser.
Q29. A patient with myocardial infarction is normally immediately given
Correct Answer: (b)
Streptokinase is a clot-buster that dissolves the thrombus in myocardial infarction.
Q30. Yeast is used in production of
Correct Answer: (c)
Yeast ferments sugars, making bread porous and producing alcohol in beer.
Q31. Non-symbiotic nitrogen fixers are
Correct Answer: (a)
Azotobacter fixes nitrogen freely in soil without a host association.
Q32. Which helps absorption of phosphorus from soil by plants?
Correct Answer: (a)
Mycorrhizal Glomus increases phosphorus uptake by plant roots.
Q33. Primitive prokaryotes responsible for biogas production from ruminant dung include
Correct Answer: (c)
Methanogens anaerobically digest dung and generate methane-rich biogas.
Q34. Select the correct group of biocontrol agents.
Correct Answer: (b)
Trichoderma, baculoviruses and Bt are important biocontrol agents.
Q35. A common biocontrol agent for control of plant diseases is
Correct Answer: (d)
Trichoderma is commonly used against plant pathogens.
Q36. Common nitrogen fixer in paddy fields is
Correct Answer: (c)
Oscillatoria is a nitrogen-fixing cyanobacterium used in paddy fields.
Q37. Probiotics are
Correct Answer: (c)
Probiotics are beneficial live microbes added to foods or supplements.
Q38. Which is wrongly matched in the table?
| Microbe | Product | Application |
|---|
| Trichoderma polysporum | Cyclosporin A | Immunosuppressive drug |
| Monascus purpureus | Statins | Lowering blood cholesterol |
| Streptococcus | Streptokinase | Removal of clot from blood vessel |
| Clostridium butylicum | Lipase | Removal of oil stains |
Correct Answer: (d)
Clostridium butylicum produces butyric acid; lipases used in detergents come from other microbes.
Q39. Bordeaux mixture was discovered as a popular fungicide against
Correct Answer: (b)
Bordeaux mixture was developed to control downy mildew of grapes.
Q40. A biocontrol agent in integrated pest management should be
Correct Answer: (a)
Good biocontrol agents target only the pest and do not harm non-target organisms.
Q41. Trichoderma harzianum is useful for
Correct Answer: (d)
T. harzianum is a biocontrol agent against soil-borne plant pathogens.
Q42. The organism used for alcoholic fermentation is
Correct Answer: (d)
Alcoholic fermentation is carried out by Saccharomyces.
Q43. What is put into an anaerobic sludge digester for further sewage treatment?
Correct Answer: (c)
Activated sludge is pumped into anaerobic digesters, where anaerobic microbes digest it and release biogas.
Q44. Which pair can both be used as biofertilisers?
Correct Answer: (d)
Cyanobacteria and Rhizobium fix nitrogen and are used as biofertilisers.
Q45. Human insulin is commercially produced from a transgenic species of
Correct Answer: (a)
Recombinant Escherichia coli is used to produce human insulin.
Q46. Which is correctly matched with its product?
Correct Answer: (c)
Yeast, Saccharomyces cerevisiae, ferments sugars to ethanol.
Q47. Which pair is wrongly matched?
Correct Answer: (c)
Vinegar is made by Acetobacter aceti, not coliform bacteria.
Q48. For retting of jute, the fermenting microbe used is
Correct Answer: (b)
Butyric-acid bacteria break down pectins and help separate jute fibres.
Q49. Monascus purpureus is used commercially for production of
Correct Answer: (d)
This yeast produces statins, which lower blood cholesterol.
Q50. The guts of cow and buffalo possess
Correct Answer: (b)
Methanogens inhabit the rumen of ruminants and produce methane.
Q51. Which pair is wrongly matched?
Correct Answer: (a)
Nitrogenase fixes nitrogen; it is not used for alcohol production.
Q52. Which statement about methanogens is not correct?
Correct Answer: (d)
Methanogens are obligate anaerobes, not aerobic organisms.
Q53. Industrial ethanol production from starch is brought about by
Correct Answer: (a)
Saccharomyces ferments sugars derived from starch into ethanol.
Q54. Over 50% higher rice yields have been reported using
Correct Answer: (a)
Azolla pinnata with Anabaena serves as an excellent paddy biofertiliser.
Q55. Which is likely to be achieved in the coming two decades?
Correct Answer: (b)
The source answer identifies improved control of cancer as the likely achievement.
Q56. Which is not true about antibiotics?
Correct Answer: (c)
Antibiotics often act against a range of susceptible microbes, not only one kind.
Q57. Which can be used as a biocontrol agent in treatment of plant disease?
Correct Answer: (a)
Trichoderma suppresses several plant pathogens.
Q58. What gases are produced in anaerobic sludge digesters?
Correct Answer: (b)
Anaerobic digestion releases methane with CO2 and traces of H2S; oxygen is absent.
Q59. A good producer of citric acid is
Correct Answer: (d)
Aspergillus niger is used commercially for citric-acid production.
Q60. Yeast Saccharomyces cerevisiae is used industrially for
Correct Answer: (c)
Brewer’s yeast produces ethanol by fermentation.
Q61. Azotobacter and Bacillus polymyxa are examples of
Correct Answer: (b)
Both are free-living nitrogen-fixing bacteria.
Q62. Match Column-I with Column-II.
| Column-I | Column-II |
|---|
| (a) Clostridium butylicum | (i) Cyclosporin-A |
| (b) Trichoderma polysporum | (ii) Butyric acid |
| (c) Monascus purpureus | (iii) Citric acid |
| (d) Aspergillus niger | (iv) Blood-cholesterol lowering agent |
Select the correct matching.
Correct Answer: (a)
C. butylicum produces butyric acid, Trichoderma produces cyclosporin A, Monascus produces statins and A. niger produces citric acid.
Q63. Which is not used in organic farming?
Correct Answer: (d)
Snails are pests, whereas mycorrhizae, earthworms and cyanobacteria support organic farming.
Q64. Which is a wrong microbe-industrial product matching?
Correct Answer: (c)
C. butylicum produces butyric acid, not lactic acid.