Class 12 Biology: Microbes In Human Welfare

Class 12 Biology

ID: 1106 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 1: Match the items in Column-A with that of Column-B: Column-A: (i) Lady bird beetle, (ii) Mycorrhiza, (iii) Biological control, (iv) Biogas. Column-B: (a) Methanobacterium, (b) Trichoderma, (c) Aphids, (d) Glomus. Choose the option that matches the items of Column A with that of B correctly:
  • A. (i)-(b), (ii)-(d), (iii)-(c), (iv)-(a)
  • B. (i)-(c), (ii)-(d), (iii)-(b), (iv)-(a)
  • C. (i)-(d), (ii)-(a), (iii)-(b), (iv)-(c)
  • D. The fourth option is incomplete in the source document.
ID: 1151 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 2: For commercial and industrial production of citric acid, which one of the following microbes is used?
  • A. Aspergillus niger
  • B. Lactobacillus sp.
  • C. Clostridium butylicum
  • D. Saccharomyces cerevisiae
ID: 1222 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 3: Bottled fruit juices are clearer as compared to those made at home, as they are clarified by the use of :
  • A. Lipases and pectinases
  • B. Pectinases and proteases
  • C. Proteases and cellulases
  • D. Nucleases and lipases
ID: 1255 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 4: Large scale industrial production of Butyric acid for human welfare is done using the microbe :
  • A. Aspergillus sp.
  • B. Streptococcus sp.
  • C. Clostridium sp.
  • D. Trichoderma sp.
ID: 1267 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 5: Large scale industrial production of Butyric acid for human welfare is done using the microbe :
  • A. Aspergillus sp.
  • B. Streptococcus sp.
  • C. Clostridium sp.
  • D. Trichoderma sp.
ID: 1279 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 6: Large scale industrial production of Butyric acid for human welfare is done using the microbe :
  • A. Aspergillus sp.
  • B. Streptococcus sp.
  • C. Clostridium sp.
  • D. Trichoderma sp.
ID: 1291 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 7: Bioactive molecule Cyclosporin A used for human welfare is derived from
  • A. Propionibacterium sharmanii
  • B. Monascus purpureus
  • C. Trichoderma polysporum
  • D. Aspergillus niger
ID: 1318 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 8: During biological treatment of sewage, the masses of bacteria held together by fungal filaments to form mesh like structures are called
  • A. primary sludge
  • B. flocs
  • C. activated sludge
  • D. anaerobic sludge
ID: 1191 Type: Assertion-reason Source: AISSCE(Board Exam) Year: 2025
Question 9: Assertion (A): Swiss cheese is characterized by large holes due to $\text{CO}_2$ production.
Reason (R): It is ripened by growing a specific fungi.
ID: 1121 Type: Very short (VSA) Source: AISSCE(Board Exam) Year: 2025
Question 10: OR (B) (i) Name an alcoholic drink which is produced by the help of microbes: (1) With distillation (2) Without distillation (ii) Explain how cyanobacteria can be used as bio-fertilizer.
ID: 1334 Type: Very short (VSA) Source: AISSCE(Board Exam) Year: 2025
Question 11: Explain how are plants benefitted by their association with "Glomus species".
ID: 1238 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
Question 12:
  • (a) What do you mean by activated sludge in an STP?
  • (b) Explain the biological treatment of the major part of the sludge transferred from the large aeration tank into the anaerobic sludge digesters before its final release into the natural water bodies.
ID: 1305 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
Question 13: Explain the biological treatment of primary effluent when passed into the large aeration tanks in a sewage treatment plant (STP).
ID: 1336 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
Question 14: Identify a, b, c, d, e and f in the table given below :
Sl. No.OrganismBioactive MoleculeUse
1.Monascus purpureusab
2.cdAntibiotic
3.eCyclosporin Af
ID: 1207 Type: Case Study Source: AISSCE(Board Exam) Year: 2025
Question 15: Study the figure given below and answer the questions that follow. [Figure is implied: Secondary Sewage Treatment Plant showing Aeration Tank, Settling Tank, Activated Sludge, etc.]
  • (a) Identify the figure and state its importance.
  • (b) Why is air diffused into the aerator tank? Explain.
  • (c) (i) What changes take place in the settling tank ?
    OR
    (c) (ii) How is BOD related to organic matter present in the water ?