Q5. Match the following microbes with their descriptions:
Column I
Column II
A. Viruses
(I) Microscopic animal/plant parasites
B. Viroids
(II) RNA only infectious agents
C. Prions
(III) Protein only infectious agents
Correct Answer: (a)
Definitions provided in the introduction (Page 1).
Q6. Flocs in secondary sewage treatment consist of:
Correct Answer: (b)
Page 6 defines flocs as masses of bacteria associated with fungal filaments.
Q7. Fermentors are used in industry to:
Correct Answer: (b)
Page 3 states that production on an industrial scale requires growing microbes in large vessels called fermentors.
Q8. Identify the correct phylum/microbe based on the statements? (i) It is a fungus used to produce citric acid. (ii) It can be grown on nutritive media to form colonies.
Q9. Identify correct statements for 'Biofertilisers': (i) They enrich the nutrient quality of the soil. (ii) Rhizobium fixes atmospheric nitrogen into organic forms. (iii) Mycorrhiza absorbs phosphorus from the soil.
Correct Answer: (a)
Standard functions of biofertilisers (section 8.6).
Q10. Assertion: Roquefort cheese is ripened by fungi.
Reason: The fungi give the cheese a particular flavour.
Correct Answer: (a)
The purpose of ripening with fungi is to develop the specific flavour.
Q11. Statins, used as blood-cholesterol lowering agents, are produced by the yeast:
Correct Answer: (c)
Page 5 states Statins are produced by the yeast Monascus purpureus.
Q12. Regarding 'Methanogens', which statements are true? (i) They grow anaerobically on cellulosic material. (ii) They produce a large amount of methane. (iii) They are found in the rumen of cattle and anaerobic sludge.
Correct Answer: (a)
Full description of methanogens from section 8.4.
Q13. Assertion: Baculoviruses are excellent for integrated pest management (IPM).
Reason: They have no negative impacts on non-target insects, mammals, or birds.
Correct Answer: (a)
Their species-specific nature makes them safe for beneficial organisms in an IPM program.
Q14. Which of the following is correct regarding 'Microbes in Household Products'? (i) Lactobacillus is used for making curd. (ii) Baker's yeast is used for bread making. (iii) Toddy is a fermented sap from palms.
Correct Answer: (a)
All three points are correctly described in section 8.1.
Q15. Bt-cotton is a plant that has been genetically engineered to express toxin genes from:
Correct Answer: (b)
Page 9 explains the introduction of B. thuringiensis (Bt) toxin genes into plants.
Q16. Which of the following organisms is used for the production of citric acid?
Correct Answer: (b)
Page 5 identifies Aspergillus niger (a fungus) as a producer of citric acid.
Q17. Match the following biofertilisers with their type:
Column I
Column II
A. Rhizobium
(I) Symbiotic fungus
B. Azospirillum
(II) Symbiotic bacterium
C. Glomus
(III) Free-living bacterium
Correct Answer: (a)
Biofertiliser categories from section 8.6.
Q18. Identify the correct statements regarding 'Antibiotics': (i) Anti means 'against' and bio means 'life'. (ii) They are 'pro-life' in the context of human beings. (iii) Penicillin was the first antibiotic discovered accidentally by Alexander Fleming.
Correct Answer: (a)
Section 8.2.2 defines antibiotics and their history.
Q19. Who discovered the first antibiotic, Penicillin?
Correct Answer: (c)
Page 4 states Alexander Fleming discovered Penicillin while working on Staphylococci bacteria.
Q20. Which are correct for 'Enzymes in Industry'? (i) Lipases are used in detergents. (ii) Pectinases are used to clarify bottled juices. (iii) Streptokinase is used as a clot buster.
Correct Answer: (a)
Industrial uses of enzymes from section 8.2.3.
Q21. Cyclosporin A is used as an ______ agent.
Correct Answer: (c)
Page 5 identifies Cyclosporin A as an immunosuppressive agent in organ-transplant patients.
Q22. Which of the following describes 'Activated Sludge' correctly? (i) It is the sediment of bacterial flocs in the settling tank. (ii) A small part is used as an inoculum in the aeration tank. (iii) The rest is pumped into anaerobic sludge digesters.
Correct Answer: (a)
Sequential flow in sewage treatment (section 8.3).
Q23. Match the following for cheese specificity:
Cheese
Feature/Microbe
A. Swiss Cheese
(I) Specific fungi
B. Roquefort Cheese
(II) Bacterium / large holes
Correct Answer: (a)
Details from section 8.1.
Q24. Match the following for sewage treatment:
Column I
Column II
A. Grit removal
(I) Secondary treatment
B. Flocs formation
(II) Primary treatment
C. Biogas production
(III) Sludge digester
Correct Answer: (a)
Stages of sewage treatment.
Q25. Assertion: High BOD of waste water indicates it is very polluted.
Reason: BOD measures the rate of oxygen uptake by micro-organisms in the water.
Correct Answer: (a)
Higher organic load leads to higher oxygen demand by microbes, indicating more pollution.
Q26. Baculoviruses of the genus ______ are used as narrow-spectrum insecticidal agents.
Correct Answer: (b)
Page 9 states the majority of baculoviruses used are in the genus Nucleopolyhedrovirus.
Q27. The 'clot buster' enzyme used to remove clots from blood vessels of heart patients is:
Correct Answer: (c)
Page 5 states Streptokinase is used as a 'clot buster' for patients with myocardial infarction.
Q28. Identify correct features of 'Rhizobium': (i) It is a symbiotic bacterium. (ii) Found in nodules of leguminous roots. (iii) Fixes atmospheric nitrogen.
Correct Answer: (a)
Standard Rhizobium description.
Q29. Assertion: LAB play a very beneficial role in our stomach.
Reason: They help in checking disease-causing microbes in the stomach.
Correct Answer: (a)
This is a direct fact from the NCERT text (Page 3).
Q30. Which are correct for 'Azospirillum' and 'Azotobacter'? (i) They are symbiotic nitrogen fixers. (ii) They are free-living in the soil. (iii) They enrich soil nitrogen content.
Correct Answer: (a)
They are free-living, not symbiotic (Page 10).
Q31. Which are true for 'Gobar Gas'? (i) Excreta of cattle is rich in methanogens. (ii) Can be used to generate biogas. (iii) technology was developed by IARI and KVIC.
Correct Answer: (a)
Section 8.4 details.
Q32. Match the bioactive molecule with its source:
Column I
Column II
A. Cyclosporin A
(I) Monascus purpureus
B. Statins
(II) Trichoderma polysporum
C. Streptokinase
(III) Streptococcus
Correct Answer: (a)
Bioactive molecule sources as per section 8.2.3.
Q33. Which insect is useful to get rid of aphids?
Correct Answer: (b)
Page 9 mentions the Ladybird beetle is useful to get rid of aphids.
Q34. Assertion: Statins act as blood-cholesterol lowering agents.
Reason: They competitively inhibit the enzyme responsible for cholesterol synthesis.
Correct Answer: (a)
Competitive inhibition is the biochemical mechanism of statin action.
Q35. Microbes are present in which of the following environments?
Correct Answer: (d)
Page 1 states microbes are present everywhere, including extreme sites like thermal vents, deep soil, and layers of snow.
Q36. Assertion: Staphlylococci could not grow around a certain mould in Fleming's experiment.
Reason: The mould Penicillium notatum produced a chemical called Penicillin.
Correct Answer: (a)
The chemical inhibited the bacterial growth.
Q37. Identify the correct phylum/group being described: (i) They are narrow-spectrum insecticidal agents. (ii) Belong to the genus Nucleopolyhedrovirus. (iii) Desirable for Integrated Pest Management.
Correct Answer: (a)
Specific features of baculoviruses.
Q38. Regarding the 'Mould' in Fleming's experiment: (i) It was Penicillium notatum. (ii) It prevented the growth of Staphylococci. (iii) It led to the discovery of antibiotics.
Correct Answer: (a)
Historical account from section 8.2.2.
Q39. Assertion: Penicillin's full potential as an antibiotic was established by Alexander Fleming.
Reason: Fleming was awarded the Nobel Prize for his discovery in 1945.
Correct Answer: (c)
Page 4 states Penicillin's full potential was established by Ernest Chain and Howard Florey, not Fleming alone.
Q40. Assertion: Prions are diverse microbes.
Reason: They are proteinaceous infectious agents.
Correct Answer: (a)
Their protein nature classifies them as a specific type of infectious microbe.
Q41. Match the nitrogen fixers:
Group
Microbe
A. Symbiotic
(I) Azotobacter
B. Free-living
(II) Rhizobium
Correct Answer: (a)
Classification of nitrogen fixers from section 8.6.
Q42. Rhizobium forms a symbiotic association with the roots of:
Correct Answer: (c)
Page 10 mentions the symbiotic association of Rhizobium on the roots of leguminous plants.
Q43. Which of the following describes 'Secondary Sewage Treatment' correctly? (i) It is primarily a physical process. (ii) Useful aerobic microbes grow into flocs. (iii) It continues until the BOD of the effluent is reduced.
Correct Answer: (a)
Primary treatment is physical; secondary is biological.
Q44. Assertion: Organic farmers do not aim to completely eradicate pests.
Reason: Without pests, beneficial predatory and parasitic insects could not survive.
Correct Answer: (a)
The organic approach maintains an ecological balance rather than total eradication.
Q45. Biological control of pests relies on ______ rather than chemicals.
Correct Answer: (b)
Page 8 states that biological control relies on natural predation.
Q46. BOD refers to the amount of ______ consumed by bacteria in one liter of water.
Correct Answer: (c)
Page 6 explains BOD (Biochemical Oxygen Demand) as the oxygen consumed if all organic matter in a liter of water were oxidized by bacteria.
Q47. Which of the following is correct for 'Biocontrol Agents'? (i) Dragonflies are used to get rid of mosquitoes. (ii) Ladybird is used to control aphids. (iii) Bt-spores are used to control butterfly caterpillars.
Correct Answer: (a)
Section 8.5 lists these specific examples.
Q48. Assertion: Cyanobacteria are autotrophic microbes.
Reason: They can fix atmospheric nitrogen in paddy fields.
Correct Answer: (a)
Autotrophy (photosynthesis) and nitrogen fixation are two separate capabilities.
Q49. Assertion: Trichoderma is used in the treatment of plant diseases.
Reason: They are free-living fungi very common in root ecosystems.
Correct Answer: (a)
Their ecological niche supports their role as biocontrol agents, but the location alone isn't the biological reason for their effectiveness.
Q50. Assertion: Biogas is a mixture of gases containing predominantly carbon dioxide.
Reason: Methanogens produce methane during the breakdown of cellulosic material.
Correct Answer: (a)
Page 7 states biogas contains predominantly methane, not carbon dioxide.
Q51. Assertion: Ganga Action Plan was initiated to save rivers from pollution.
Reason: Untreated sewage often leads to water-borne diseases.
Correct Answer: (a)
The link between sewage and disease necessitated the cleanup plans.
Q52. Regarding 'Baculoviruses', identify the correct statements: (i) They belong to the genus Nucleopolyhedrovirus. (ii) They are excellent for species-specific insecticidal applications. (iii) They have negative impacts on non-target birds.
Correct Answer: (a)
They have no negative impact on non-target organisms (Page 9).
Q53. Lactic acid bacteria (LAB) improve the nutritional quality of milk by increasing which vitamin?
Correct Answer: (b)
Page 3 mentions that LAB improves nutritional quality by increasing Vitamin B12.
Q54. Assertion: Single Cell Protein (SCP) involves the use of microbes.
Reason: Microbes are used as a source of energy in rural areas.
Correct Answer: (b)
Biogas, not SCP, is used as energy in rural areas.
Q56. Match the following for biogas plant (Figure 8.8):
Structure
Description
A. Digester
(I) 10-15 feet deep tank
B. Gas-holder
(II) Floating cover
Correct Answer: (a)
Labels from the biogas plant diagram.
Q57. Assertion: MTP is performed to get rid of unwanted pregnancy due to rapes.
Reason: Government of India legalised MTP in 1971.
Correct Answer: (a)
Legalization allows the procedure, but the reason for the procedure itself is the unwanted pregnancy.
Q58. Select correct statements for 'Biogas': (i) It is a mixture of gases containing predominantly methane. (ii) It is inflammable. (iii) It is used as a source of energy for cooking and lighting.
Correct Answer: (a)
Properties and uses of biogas from section 8.4.
Q59. Correct statements for 'Mycorrhiza' include: (i) Many members of genus Glomus form it. (ii) Fungus provides phosphorus to the plant. (iii) Plant provides resistance to root-borne pathogens.
Correct Answer: (a)
Mutualistic benefits listed on page 10.
Q60. Which of the following is used as a biofertiliser in paddy fields?
Correct Answer: (b)
Page 10 states that in paddy fields, cyanobacteria serve as an important biofertiliser.
Q61. Correct statements for 'Primary Sludge' include: (i) All solids that settle during primary treatment. (ii) It is taken for secondary treatment.
Correct Answer: (a)
The effluent (supernatant) is taken for secondary treatment, not the sludge (Page 6).
Q62. Match the biocontrol agent with its target:
Column I (Agent)
Column II (Target)
A. Ladybird
(I) Mosquitoes
B. Dragonflies
(II) Aphids
C. Bt-toxin
(III) Butterfly caterpillars
Correct Answer: (a)
Standard biocontrol targets from section 8.5.
Q63. Select correct statements for 'Organic Farming': (i) Uses biofertilisers instead of chemical fertilisers. (ii) Aim is to enrich the nutrient quality of soil. (iii) Prevents environmental pollution.
Correct Answer: (a)
Philosophy of biofertiliser use (section 8.6).
Q64. Assertion: Bottled juices are clearer than home-made ones.
Reason: Bottled juices are clarified using lipases.
Correct Answer: (a)
Bottled juices are clarified using pectinases and proteases, not lipases.
Q65. Assertion: Glomus helps plants tolerate salinity and drought.
Reason: The fungus absorbs phosphorus and passes it to the plant.
Correct Answer: (a)
Phosphorus absorption is the main function; salt/drought tolerance is an additional benefit listed in the text.
Q66. Identify correct statements for 'Bt-toxin': (i) Produced by Bacillus thuringiensis. (ii) Available in sachets as dried spores. (iii) Kills insect larvae in their gut.
Q67. Assertion: Secondary sewage treatment is also called biological treatment.
Reason: It involves the use of heterotrophic aerobic microbes to consume organic matter.
Correct Answer: (a)
The reliance on living organisms for treatment is why it is termed 'biological'.
Q68. Assertion: All microbes are harmful to human beings.
Reason: Microbes cause a large number of diseases in humans, animals, and plants.
Correct Answer: (d)
Page 3 notes that while many cause disease, several microbes are useful to man in diverse ways.
Q69. The technology of biogas production in India was developed mainly due to the efforts of:
Correct Answer: (a)
Page 8 mentions the efforts of Indian Agricultural Research Institute (IARI) and Khadi and Village Industries Commission (KVIC).
Q70. Mycorrhiza is a symbiotic association between fungi and plants, where the fungus helps in absorbing:
Correct Answer: (c)
Page 10 states that the fungal symbiont in mycorrhiza (e.g., Glomus) absorbs phosphorus from soil.
Q71. In sewage treatment, primary treatment involves:
Correct Answer: (b)
Page 6 defines primary treatment as the physical removal of large and small particles through filtration and sedimentation.
Q72. Which of the following is correct? (i) Viruses, viroids and prions are microbes. (ii) Microbes like bacteria can form colonies on nutritive media. (iii) Antibiotics can treat diseases like plague and leprosy.
Correct Answer: (a)
Standard introductory and industrial facts from the chapter.
Q73. Regarding 'Statins', identify true statements: (i) Produced by Monascus purpureus. (ii) Competitively inhibit cholesterol synthesis enzyme. (iii) Act as blood-cholesterol lowering agents.
Correct Answer: (a)
Mechanism and source from section 8.2.3.
Q74. Assertion: Anaerobic sludge digesters produce biogas.
Reason: Bacteria produce methane, hydrogen sulphide, and CO2 in these tanks.
Correct Answer: (a)
The product of the digestion is the gas mixture known as biogas.
Q75. Which are correct for 'Cyanobacteria'? (i) They are autotrophic microbes. (ii) They add organic matter to the soil. (iii) They are used as biofertilisers in paddy fields.
Correct Answer: (a)
Standard biofertiliser facts (section 8.6).
Q76. Regarding 'Lactic Acid Bacteria' (LAB): (i) Grow in milk and convert it to curd. (ii) Produce acids that coagulate milk proteins. (iii) Check disease-causing microbes in the stomach.
Correct Answer: (a)
Full list of LAB benefits from section 8.1.
Q77. Which of the following are correct regarding 'BOD'? (i) BOD measures the rate of oxygen uptake by micro-organisms. (ii) Higher BOD means the water is less polluting. (iii) BOD is a measure of organic matter present in water.
Correct Answer: (a)
Higher BOD means more polluting potential (Page 6).
Q78. Which bacteria are found in the rumen of cattle and help in cellulose digestion?
Correct Answer: (b)
Page 7 states methanogens (Methanobacterium) are present in the rumen and help break down cellulose.
Q79. Assertion: Activated sludge is used as an inoculum in the aeration tank.
Reason: A small part of the activated sludge contains useful aerobic microbes.
Correct Answer: (a)
Inoculum provides the starter microbes to begin secondary treatment.
Q80. Assertion: Ladybird is a biocontrol agent.
Reason: It helps get rid of mosquitoes.