Zoology 2023 Paper I 50 marks Explain

Q8

(a) What is ELISA? Explain the principle, types, procedure and applications of ELISA. (20 marks) (b) Describe the symptoms, diagnosis, treatment and preventive measures of livestock diseases. (15 marks) (c) Define crypsis. Explain the types and mechanism of crypsis in animals with suitable examples. (15 marks)

हिंदी में प्रश्न पढ़ें

(a) ई० एल० आई० एस० ए० क्या है? ई० एल० आई० एस० ए० के सिद्धांत, प्रकार, प्रक्रिया और अनुप्रयोगों की व्याख्या कीजिए। (20 अंक) (b) पशुधन रोगों के लक्षण, निदान, उपचार और रोकथाम के उपायों का वर्णन कीजिए। (15 अंक) (c) गोपकता (क्रिप्सिस) को परिभाषित कीजिए। प्राणियों में गोपकता के प्रकार और क्रियाविधि का उपयुक्त उदाहरणों सहित वर्णन कीजिए। (15 अंक)

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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, logical exposition of mechanisms and principles across all three sub-parts. Allocate approximately 40% of time/words to part (a) ELISA (20 marks), 30% to part (b) livestock diseases (15 marks), and 30% to part (c) crypsis (15 marks). Structure with brief definitions, detailed mechanistic explanations, and conclude with integrated applications—biomedical for (a), veterinary economy for (b), and evolutionary ecology for (c).

Key points expected

  • Part (a): ELISA principle based on antigen-antibody interaction with enzyme-mediated colorimetric detection; distinction between direct, indirect, sandwich and competitive ELISA with their specific applications in disease diagnosis
  • Part (a): Step-wise procedure including coating, blocking, incubation, washing and substrate addition; applications in HIV, hepatitis, COVID-19 detection and veterinary serology
  • Part (b): Major livestock diseases (FMD, anthrax, black quarter, mastitis) with species-specific symptoms; differential diagnosis combining clinical signs, laboratory tests and post-mortem findings
  • Part (b): Treatment protocols including antibiotics, antivirals, supportive therapy; preventive measures—vaccination schedules (FMD-Raksha vaccine), biosecurity, quarantine and herd health programs in Indian context
  • Part (c): Crypsis as visual concealment through background matching, disruptive coloration, countershading and masquerade; mechanistic explanation involving predator-prey sensory physiology and signal-to-noise processing
  • Part (c): Indian examples—chameleon color change, leaf insect (Phyllium) masquerade, tiger stripes in Ranthambore grasslands; evolutionary arms race and frequency-dependent selection maintaining cryptic polymorphisms

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness22%11For (a), accurately distinguishes all four ELISA types with correct immunological principles; for (b), correctly identifies etiological agents and pathophysiology of major livestock diseases; for (c), precisely defines crypsis categories without confusing with mimicry or aposematismBasic definitions correct but ELISA types confused or disease agents misidentified; crypsis broadly defined without categorical precisionFundamental errors—ELISA described as PCR variant, viral/bacterial diseases conflated, crypsis equated with Batesian mimicry
Diagram / labelling18%9For (a), schematic of sandwich ELISA with labelled layers (capture Ab, antigen, detection Ab-enzyme conjugate, substrate); for (c), annotated diagrams showing disruptive patterns and countershading gradient; clear hand-drawn quality with directional arrowsGeneric ELISA plate diagram without molecular detail; crypsis described textually without visual representation; labels incompleteNo diagrams despite visual nature of question; or irrelevant illustrations (flowcharts instead of mechanistic diagrams)
Examples & nomenclature20%10For (a), specific kits (HIV ELISA, Pregnancy hCG kits); for (b), Indian livestock context—FMD virus serotypes O, A, Asia 1; for (c), precise taxonomic names (Phyllium bioculatum, Panthera tigris) with habitat specificity (Western Ghats, Sundarbans)Generic examples without specificity; 'some insects' instead of named species; 'common cattle diseases' without FMD/anthrax distinctionNo examples or factually wrong ones; invented species names;混淆 disease symptoms across host species
Process explanation22%11For (a), sequential biochemical steps with rationale for each wash/incubation; for (b), diagnostic algorithm from clinical suspicion to confirmatory test; for (c), sensory processing mechanism—how predator visual systems detect edges and how crypsis disrupts Gestalt perceptionChronological listing without causal explanation; diagnostic steps as bullet points without reasoning; crypsis as 'hiding' without perceptual mechanismIllogical sequence; missing critical steps; no mechanistic understanding—'enzyme makes color' without substrate conversion explanation
Evolutionary / applied context18%9For (a), discusses ELISA evolution from RIA and its role in India's National AIDS Control Programme; for (b), economic impact on dairy sector (Operation Flood legacy) and One Health approach; for (c), frequency-dependent selection, industrial melanism in Biston betularia as classic evolutionary demonstrationBrief mention of applications without integration; generic 'important for farmers'; crypsis as 'useful for survival' without selection mechanismNo applied context; purely descriptive without connecting to broader significance; or irrelevant digressions into unrelated evolutionary theory

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