Paper I — Q8
(a) Define gene frequency. Describe the method of estimation of gene frequency from genotypic frequency with the help of a…
(a) Define gene frequency. Describe the method of estimation of gene frequency from genotypic frequency with the help of a suitable example. (20 marks) (b) Write the role of NDDB in rural development. (10 marks) (c) Write short notes on the following: (5×4=20 marks) (i) Methane inhibitors (ii) Role of rumen in feed fermentation (iii) Chemical regulation of respiration (iv) Blood-brain barrier
हिंदी में प्रश्न पढ़ें
(a) जीन आवृत्ति को परिभाषित कीजिये। उपयुक्त उदाहरण की सहायता से जीनोटाइपिक आवृत्ति से जीन आवृत्ति के आकलन की विधि का वर्णन कीजिये। (20 अंक) (b) ग्रामीण विकास में एन.डी.डी.बी. की भूमिका के बारे में लिखिए। (10 अंक) (c) निम्नलिखित पर संक्षिप्त टिप्पणी लिखे : (5×4=20 अंक) (i) मीथेन अवरोधक (ii) फीड किण्वन में रूमेन की भूमिका (iii) श्वसन का रासायनिक नियमन (iv) रक्त-मस्तिष्क अवरोधक
Directive word: Describe
This question asks you to describe. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.
See our UPSC directive words guide for a full breakdown of how to respond to each command word.
How this answer will be evaluated
Approach
The primary directive is 'describe' for part (a), with 'write' for (b) and 'write short notes' for (c). Allocate approximately 40% of time/words to part (a) given its 20 marks, 20% to part (b), and 40% distributed across the four short notes in (c). Structure as: concise definitions for (a), followed by mathematical derivation with worked example; bullet-pointed institutional analysis for (b); and four distinct, evenly-developed short notes for (c)(i)-(iv), each with definition-mechanism-significance.
Key points expected
- Part (a): Precise definition of gene frequency (allele frequency) as proportion of a specific allele in a gene pool; Hardy-Weinberg equilibrium equation (p² + 2pq + q² = 1) with clear derivation showing p = D + ½H and q = R + ½H where D, H, R are genotypic frequencies
- Part (a): Worked numerical example (e.g., MN blood group system in Indian cattle breeds or human populations) showing step-by-step calculation from observed genotypic counts to estimated gene frequencies
- Part (b): NDDB's establishment (1965), Operation Flood phases, Anand Pattern cooperatives, role in rural livelihood security, women empowerment through dairy cooperatives, and recent initiatives like National Dairy Plan
- Part (c)(i): Methane inhibitors—definition, types (ionophores like monensin, chemical inhibitors like 3-NOP, plant bioactive compounds), mode of action on methanogenic archaea, and environmental significance
- Part (c)(ii): Rumen fermentation—anatomical compartments, microbial ecosystem (bacteria, protozoa, fungi), fermentation end-products (VFA, microbial protein), and factors affecting fermentation efficiency
- Part (c)(iii): Chemical regulation of respiration—peripheral and central chemoreceptors, CO₂/H⁺/O₂ sensing, medullary respiratory centers, and feedback mechanisms
- Part (c)(iv): Blood-brain barrier—structural components (tight junctions, astrocytes, pericytes), selective permeability, protective function, and clinical relevance (drug delivery challenges)
Evaluation rubric
| Dimension | Weight | Max marks | Excellent | Average | Poor |
|---|---|---|---|---|---|
| Demand-directive understanding | 15% | 7.5 | For (a), provides both formal definition AND derives estimation method mathematically; for (b), treats 'role' comprehensively across economic, social and institutional dimensions; for (c), each short note addresses 'what' and 'why' within word economy, respecting the 5×4 mark distribution | Defines gene frequency adequately but derivation incomplete; lists NDDB activities without analytical framing of 'role'; short notes are descriptive but miss mechanism or significance in 1-2 sub-parts | Confuses gene frequency with genotypic frequency; treats NDDB as mere historical narrative; writes disproportionately long notes for some sub-parts while neglecting others |
| Content depth & accuracy | 25% | 12.5 | Mathematically accurate Hardy-Weinberg derivation with correct allele counting; NDDB analysis includes post-Operation Flood evolution and current NDP-I/II; physiological notes demonstrate integration (e.g., links methane inhibition to enteric fermentation biochemistry, or BBB structure to therapeutic implications) | Correct formulas but arithmetic errors in example; NDDB coverage stops at Operation Flood; physiological descriptions accurate but lack integrative depth across notes | Incorrect formulas (e.g., p = D + H + R); factual errors about NDDB establishment or Operation Flood dates; fundamental misconceptions in physiological mechanisms (e.g., confusing BBB with blood-CSF barrier) |
| Structure & flow | 20% | 10 | Clear tripartite division with visible sub-part labeling; (a) progresses logically definition→derivation→example; (b) uses thematic sub-headings; (c) maintains uniform depth across four notes with consistent internal structure (definition-mechanism-application) | All parts addressed but (a) lacks clear separation between definition and estimation method; (b) reads as chronology rather than thematic analysis; (c) notes vary in completeness | Poor or missing sub-part labeling causing confusion; (a) presents example before establishing principles; (b) and (c) appear as undifferentiated blocks of text |
| Examples / case-law / data | 25% | 12.5 | For (a), authentic numerical example with Indian context (e.g., haemoglobin variants in Indian breeds, or MN blood groups); for (b), specific data on milk production growth, cooperative membership numbers, or NDDB's impact on rural income; for (c), named compounds (monensin, 3-NOP, lasalocid), specific VFA proportions, or clinical conditions affecting BBB integrity | Generic example for (a) without Indian specificity; NDDB description lacks quantitative evidence; physiological notes mention categories without specific instances | No worked numerical example in (a); no data or specific schemes for NDDB; physiological notes entirely theoretical without named substances or conditions |
| Conclusion & analytical edge | 15% | 7.5 | Brief synthesizing conclusion for (a) on applications in conservation genetics or breed improvement; for (b), critical assessment of NDDB challenges (market volatility, AI integration, climate resilience); for (c), forward-looking note on emerging alternatives (e.g., red seaweed for methane inhibition, precision delivery for BBB penetration) | Summative statements without critical evaluation; acknowledges NDDB success without addressing contemporary challenges; notes end descriptively | No concluding element; purely informational treatment throughout; fails to demonstrate why the content matters for veterinary practice or rural development policy |
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