Chapter Overview & Weightage
- Marks in Boards: 6–10 marks (usually 1–2 questions + application-based)
- Repeated Topics: Bt cotton, RNAi, gene therapy, molecular diagnostics, transgenic animals, ethical issues, GEAC, biopiracy.
- Difficulty: Moderate • Heavy on applications, advantages, criticisms & ethical concerns.
- Trend (2021–2025): 1 case-based/application (4 marks) on Bt crops/RNAi + 1 long answer (5 marks) on gene therapy/transgenics + MCQs on ethical issues.
Most Important & Repeated Questions (2021–2025)
- Repeated 5–6 times: Explain Bt cotton. How does it provide resistance against bollworms? (5 marks)
- Repeated 4–5 times: What is RNAi? Explain its role in gene silencing with example (nematode resistance in tobacco). (5 marks)
- Repeated 4 times: Describe applications of biotechnology in human health (gene therapy, molecular diagnostics, vaccines). (5 marks)
- Repeated 3–4 times: What are transgenic animals? Give examples & their uses. (3 marks)
- Repeated 3 times: Explain ethical issues in biotechnology (GEAC, biopiracy, patenting). (3 marks)
- Repeated 3 times: What is molecular diagnosis? Explain PCR & ELISA in disease detection. (3 marks)
- Repeated 2–3 times: Discuss advantages & limitations of genetic engineering in agriculture. (3 marks)
- Assertion-Reason (2023–2025): Assertion: Bt toxin is insect-specific. Reason: It is activated in alkaline gut of insects. (Both true, reason explains – repeated 2x)
Important Keywords & Concepts to Memorize
- Biotechnology applications, Bt cotton, cry gene, Bacillus thuringiensis, RNAi (RNA interference), dsRNA, Agrobacterium tumefaciens, Ti plasmid, gene therapy (ADA-SCID), molecular diagnostics (PCR, ELISA), transgenic animals (Rosie cow, GloFish), ethical issues, GEAC (Genetic Engineering Approval Committee), biopiracy, patenting, Basmati rice controversy, golden rice, Flavr Savr tomato, edible vaccines, recombinant therapeutics (insulin, growth hormone), monoclonal antibodies.
Exam Strategy for Chapter 12 (2026 Boards)
- Focus: Bt cotton mechanism + RNAi process – practice 3 daily
- High-scoring: Applications in health (gene therapy, diagnostics) – 5 marks
- Time: 8–10 minutes per 5-mark question
- Tip: Use flowcharts for Bt toxin action & RNAi – neatness = full marks
- Repeated: Ethical issues & biopiracy (2–3 marks)
This is Chapter 12 complete PYQ analysis.
If you want Chapter 13 or any other chapter, just say the chapter number or name.