Class 12/Question Bank/Competency Based
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
BioNotesBioNotesCreated by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Competency Based Questions on Microbes in Human Welfare
1. Analyze the Process: In a sewage treatment plant, the "Primary Treatment" step removes floating debris and grit. If this step is skipped, what will be the most immediate consequence for the "Secondary Treatment"? a) The anaerobic sludge digesters will fail. b) The aeration tanks will get clogged with solid inorganic matter, reducing efficiency. c) Biogas production will increase. d) Flocs will not form.
2. Evaluate the Application: A farmer wants to grow a crop without using chemical nitrogen fertilizers. Which of the following microbes should he use as a biofertilizer for a paddy (rice) field? a) Rhizobium b) Glomus (Mycorrhiza) c) Anabaena (Cyanobacteria) d) Lactobacillus
3. Assertion (A): Bottled fruit juices bought from the market are clearer than those made at home. Reason (R): The bottled juices are treated with pectinases and proteases. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true.
4. Identify the Bioactive Molecule: A patient undergoing a kidney transplant is prescribed a drug derived from Trichoderma polysporum. What is the function of this drug? a) To bust blood clots. b) To lower blood cholesterol. c) To suppress the immune system and prevent organ rejection. d) To treat bacterial infection.
5. Predict the Outcome: If oxygen supply to the activated sludge tank (aeration tank) in an STP is cut off, what will happen to the BOD of the effluent? a) BOD will decrease rapidly. b) BOD will increase or remain high because aerobic bacteria will die. c) BOD will become zero. d) Methane production will start immediately in the aeration tank.
6. Biocontrol Logic: Why is Nucleopolyhedrovirus (NPV) considered an excellent candidate for Integrated Pest Management (IPM)? a) It kills all insects in the field. b) It is a broad-spectrum insecticide. c) It is species-specific and does not harm non-target organisms like bees and birds. d) It acts faster than chemical pesticides.
7. Microbial Product: Which of the following matches is incorrect regarding the microbe and its industrial product? a) Acetobacter aceti - Acetic Acid b) Clostridium butylicum - Lactic Acid c) Aspergillus niger - Citric Acid d) Saccharomyces cerevisiae - Ethanol
8. Analyze the Graph: During sewage treatment, as the microbial "flocs" grow in the aeration tank, the BOD of the water drops. What does this drop in BOD indicate? a) Increase in polluting potential. b) Decrease in dissolved oxygen. c) Consumption of organic matter by microbes. d) Increase in pathogenic bacteria.
9. Differentiate: What is the key difference in the production of Whisky versus Wine? a) Whisky is fermented; Wine is distilled. b) Whisky is distilled; Wine is produced without distillation. c) Whisky uses fruit juices; Wine uses cereals. d) Whisky uses bacteria; Wine uses yeast.
10. Reasoning: Why does "Swiss Cheese" have large holes? a) Due to the burrowing of mites. b) Due to the production of large amounts of CO2 by Propionibacterium shermanii. c) Due to the escape of water vapor during baking. d) Due to the addition of baking soda.
11. Mechanism of Action: How do Statins lower blood cholesterol? a) By breaking down cholesterol in the blood. b) By inhibiting the absorption of cholesterol in the intestine. c) By competitively inhibiting the enzyme responsible for cholesterol synthesis. d) By increasing the excretion of cholesterol.
12. Identify the Component: In a biogas plant, the "slurry" consists of: a) Only Methane. b) Dung and water. c) Only dry leaves. d) Activated sludge.
13. Biofertilizer Application: Which of the following is a free-living nitrogen-fixing bacterium? a) Rhizobium b) Glomus c) Azospirillum d) Frankia
14. Process Analysis: In the secondary treatment of sewage, what happens to the "Activated Sludge"? a) It is all pumped back into the aeration tank. b) A small part is pumped back as inoculum, and the rest goes to anaerobic sludge digesters. c) It is released into the river. d) It is dried and sold as chemical fertilizer.
15. Critical Thinking: Why are antibiotics not effective against the common cold? a) The virus has a cell wall that is resistant. b) The common cold is caused by a virus, and antibiotics only target bacteria. c) The dose is usually too low. d) The virus mutates too fast.
Rohan adds a small amount of curd (inoculum) to fresh milk and keeps it at room temperature. After a few hours, the milk turns into curd. However, his friend tries the same experiment but keeps the milk in the refrigerator. The milk does not set.
16. Explain: Why did the milk not turn into curd in the refrigerator?
17. Identify: Curd is more nutritious than milk because it contains increased:
18. Application: Role of LAB in the human stomach?
A city discharges untreated sewage into a river. Fish start dying.
19. Predict: Relationship between BOD and DO at the point of discharge?
20. Reasoning: Why do the fish die?
21. Solution: Which stage reduces this high BOD?
A farmer uses Bt Cotton to avoid pesticide costs.
22. Mechanism: How does it protect against Bollworms?
23. Safety: Is it harmful to humans?
24. Designing a Biogas Plant: You are designing a biogas plant for a village.
25. Creating a Process Flow: Industrial Penicillin.
26. Formulating a Hypothesis: Legume vs. Cereal.
27. Scenario Analysis (Biofertilizers): "Instant" vs "Slow".
28. Critical Analysis: "Antibiotic Resistance."
29. Developing a Product: Super Detergent.
30. Debating Energy: Biofuels vs Biogas.