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Predicted Questions with Model Answers
Q1 (5 marks — 50 words): What is CRISPR-Cas9? Who developed it and what is its first approved therapeutic application?
Model Answer:
CRISPR-Cas9 is a gene editing technology derived from a bacterial immune system. A guide RNA directs the Cas9 protein to cut DNA at a precise target sequence, enabling gene insertion, deletion, or replacement. Developed by Jennifer Doudna and Emmanuelle Charpentier (Nobel Prize Chemistry, 2020). First approved therapeutic application: CASGEVY (CTX001) — approved by FDA in December 2023 for sickle cell disease and beta-thalassaemia. India's FelUDA used CRISPR for COVID-19 diagnostics (DCGI approved, 2021).
Q2 (5 marks — 50 words): How do mRNA vaccines work? How do they differ from conventional vaccines?
Model Answer:
mRNA vaccines inject lipid nanoparticle-encased mRNA encoding a pathogen antigen (e.g., COVID-19 spike protein). Host cell ribosomes translate mRNA → produce antigen protein → immune response activated → memory cells formed. mRNA never enters nucleus and cannot integrate into DNA; degraded within days. Conventional vaccines use killed/weakened pathogens or proteins. Advantages: Design in weeks (once genome sequenced); no live pathogen needed. Nobel Prize in Physiology 2023 awarded to Karikó and Weissman for enabling mRNA vaccine technology.
Q3 (5 marks — 50 words): What is fermentation? Differentiate between alcoholic and lactic acid fermentation with examples.
Model Answer:
Fermentation is the anaerobic microbial breakdown of organic compounds (sugars) to simpler molecules, producing ATP. Alcoholic fermentation (Saccharomyces yeast): C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ — used in beer, wine, bioethanol production, and bread leavening (CO₂ makes bread rise). Lactic acid fermentation (Lactobacillus bacteria): glucose → lactic acid — used in curd/yogurt, cheese, silage. Industrial scale: penicillin, citric acid, recombinant insulin all produced via fermentation in bioreactors.
Q4 (5 marks — 50 words): What is Bt cotton? State one benefit and one controversy related to GMO crops in India.
Model Answer:
Bt cotton is India's only commercially approved GM crop (since 2002), containing the Cry protein gene from Bacillus thuringiensis — toxic to bollworm insects but safe for humans. Benefit: Reduced bollworm damage → pesticide use fell ~40%; increased cotton yields → India became world's largest cotton producer. Controversy: Bt brinjal — approved by GEAC in 2010 but Environment Minister Jairam Ramesh imposed moratorium citing inadequate safety testing, biodiversity concerns, and farmers' rights; moratorium remains in force.
Q5 (5 marks — 50 words): What is the Jaipur Foot? What is its significance in biomedical technology?
Model Answer:
Jaipur Foot is a low-cost, high-durability prosthetic limb developed in Rajasthan by orthopaedic surgeon Dr. P.K. Sethi and craftsman Ramchandra Sharma Vishwakarma in 1968. Designed for India's rural terrain — allows squatting, walking on uneven ground, and wearing footwear. Made from vulcanised rubber and wood; costs ~₹45,000 (vs. ₹10 lakh for imported prosthetics). Used by 1.3 million+ amputees in 26 countries. Recognised by Time magazine as one of the best inventions of the 20th century.
Q6 (5 marks — 50 words): Distinguish between innate and adaptive immunity. What is the role of memory cells in vaccination?
Model Answer:
Innate immunity is non-specific, immediate, inborn — skin barrier, phagocytes (neutrophils, macrophages), inflammation, fever. Adaptive immunity is specific, slower (days), improves with exposure — B cells produce antigen-specific antibodies (humoral); T cells attack infected cells (cell-mediated). Memory cells (long-lived B and T cells formed after first exposure) enable rapid, massive immune response on re-exposure to the same pathogen. Vaccines mimic natural infection to generate memory cells without causing disease — on actual pathogen entry, memory cells mount protection before illness develops.