Q6
(a) Define air pollution. Explain the types, sources, consequences and control measures of air pollution. 20 (b) Define pheromones. Discuss the role of pheromones in alarm spreading in animals with suitable examples. 15 (c) What is DNA fingerprinting? Explain the mechanism and applications of DNA fingerprinting in forensic science. 15
हिंदी में प्रश्न पढ़ें
(a) वायु प्रदूषण को परिभाषित कीजिए। वायु प्रदूषण के प्रकार, स्रोत, परिणाम और नियंत्रण के उपायों की व्याख्या कीजिए। 20 (b) फेरोमोन को परिभाषित कीजिए। जानवरों के संचेतन प्रसार (अलार्म स्प्रेडिंग) में फेरोमोन की भूमिका की उपयुक्त उदाहरणों सहित चर्चा कीजिए। 15 (c) डी० एन० ए० फिंगरप्रिंटिंग क्या है? फोरेंसिक विज्ञान में डी० एन० ए० फिंगरप्रिंटिंग की क्रियाविधि एवं अनुप्रयोगों की व्याख्या कीजिए। 15
Directive word: Explain
This question asks you to explain. 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 directive 'explain' demands clear exposition with causal reasoning across all three parts. Allocate approximately 40% of time/words to part (a) given its 20 marks, and roughly 30% each to parts (b) and (c). Structure as: brief definitions for each sub-part, followed by systematic elaboration of requested components (types/sources/consequences/controls for air pollution; mechanism/examples for alarm pheromones; technique/applications for DNA fingerprinting), with a concluding synthesis on chemical communication and molecular techniques in zoology.
Key points expected
- Part (a): Definition of air pollution (WHO/EPA criteria); classification into primary vs secondary pollutants, particulate vs gaseous; major sources (natural: dust, volcanic; anthropogenic: vehicular, industrial, thermal power, agricultural burning); health and ecological consequences (respiratory diseases, acid rain, global warming, eutrophication); control measures (legislative: Air Act 1981, BS-VI norms; technological: scrubbers, electrostatic precipitators, catalytic converters; biological: urban greening)
- Part (b): Definition of pheromones (Karlson & Lüscher 1959); distinction from allomones and kairomones; alarm pheromone mechanism (release-detection-response cascade); specific examples: honeybee (Apis mellifera) isoamyl acetate, ant (Formica) formic acid, fish (Ostariophysi) alarm substance (Schreckstoff), aphids (E)-β-farnesene
- Part (c): Definition of DNA fingerprinting (Alec Jeffreys 1984); mechanism details: VNTR/minisatellite or STR analysis, PCR amplification, gel electrophoresis/Southern blotting, DNA profiling; forensic applications: criminal identification (Nirbhaya case), paternity disputes, wildlife forensics (tiger/poaching cases), disaster victim identification, exoneration of falsely accused
Evaluation rubric
| Dimension | Weight | Max marks | Excellent | Average | Poor |
|---|---|---|---|---|---|
| Concept correctness | 22% | 11 | Precise WHO definition of air pollution; accurate distinction between primary/secondary pollutants with correct chemical equations (e.g., NOx + VOCs → ozone); correct biochemical classification of pheromones; accurate description of VNTR/STR methodology including primer design and statistical interpretation of match probability | Broadly correct definitions but conflates photochemical smog with industrial smog; treats all chemical signals as pheromones without distinction; describes DNA fingerprinting vaguely as 'DNA matching' without specifying repetitive sequences or PCR role | Incorrect definition (confuses pollution with pollutants); describes hormones instead of pheromones; fundamental errors in DNA technology (confuses with DNA sequencing or RNA interference) |
| Diagram / labelling | 18% | 9 | At least two relevant diagrams: e.g., schematic of electrostatic precipitator or catalytic converter for (a); labeled diagram of alarm pheromone release-detection pathway in social insects for (b); clear illustration of DNA fingerprint gel pattern with bands, lanes, and size markers for (c); all diagrams properly titled and integrated with text | One diagram present but incomplete labeling; OR diagrams mentioned but not drawn; flowcharts substitute for structural diagrams without clear relevance | No diagrams despite clear visual components in all three parts; OR diagrams drawn but completely unlabeled and unrelated to question requirements |
| Examples & nomenclature | 20% | 10 | Specific chemical names: isoamyl acetate, 2-heptanone (honeybee alarm); hypoxanthine-3-N-oxide (fish alarm substance); specific Indian context: Delhi air quality index, Supreme Court orders on firecrackers; forensic cases: Nirbhaya, Aarushi Talwar, or wildlife cases like tiger ST-13 poaching; correct scientist attributions (Jeffreys, Butenandt) | Generic examples ('bees', 'ants') without species or chemical specificity; mentions Indian cities for pollution but no specific data or policies; forensic applications listed without case references | No specific examples; invented chemical names; confused examples (using butterfly mimicry for alarm pheromones); irrelevant case references |
| Process explanation | 22% | 11 | Clear stepwise mechanisms: for air pollution—formation of secondary pollutants via photochemical reactions; for alarm spreading—release, propagation, receiver sensory detection, behavioral response cascade; for DNA fingerprinting—extraction, PCR amplification with Taq polymerase, STR analysis, capillary electrophoresis, CODIS database matching with explanation of statistical significance | Lists steps without causal connections; describes outcomes without mechanisms; conflates different analytical techniques (RFLP vs PCR-based methods) | No process explanation; merely defines terms; confused chronology in DNA fingerprinting steps; describes control measures as processes |
| Evolutionary / applied context | 18% | 9 | Evolutionary interpretation: kin selection explaining alarm pheromone evolution (Hamilton's rule), cost-benefit analysis of alarm calling; applied integration: One Health approach linking air pollution, animal health, and forensic biodiversity; mention of DNA barcoding complementing fingerprinting; future directions: CRISPR-based forensic tools, pheromone-based pest management | Brief mention of 'evolutionary advantage' without elaboration; lists applications without connecting to broader zoological or societal context | No evolutionary or applied context; purely descriptive answer without synthesis; irrelevant philosophical digressions |
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