Zoology 2024 Paper II 50 marks Discuss

Q8

(a) Write about the role of liver and pancreas in digestion. Add a note on neural and hormonal regulation of their secretions. (15+5=20 marks) (b) Discuss the role of oxidative phosphorylation in cellular and tissue metabolism. (15 marks) (c) Describe the organogenesis of eye. (15 marks)

हिंदी में प्रश्न पढ़ें

(a) पाचन में यकृत एवं अग्न्याशय की भूमिका के बारे में लिखिए। इनके स्रवण के तंत्रिकीय एवं हार्मोनी नियमन पर एक टिप्पणी लिखिए। (15+5=20 अंक) (b) कोशिकीय एवं उत्तक उपापचय में ऑक्सीकरणी (ऑक्सीडेटिव) फॉस्फोरिलेशन की भूमिका का वर्णन कीजिए। (15 अंक) (c) नेत्र के अंगविकास का वर्णन कीजिए। (15 अंक)

Evaluate your answer to this question → See all 2024 Zoology questions

Directive word: Discuss

This question asks you to discuss. 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 'discuss' requires a comprehensive, analytical treatment with balanced coverage across all three sub-parts. Allocate approximately 40% of time/words to part (a) given its 20 marks, and 30% each to parts (b) and (c). Structure with a brief integrative introduction, then dedicated sections for each sub-part with clear sub-headings, followed by a concluding synthesis on how digestive-metabolic-organogenetic processes interconnect in organismal biology.

Key points expected

  • Part (a): Liver's role in bile production (bile salts, bilirubin metabolism), emulsification of lipids; pancreas exocrine functions (amylase, lipase, proteases in pancreatic juice) and endocrine role (insulin, glucagon); neural regulation (vago-vagal reflexes, cephalic phase) and hormonal regulation (secretin, CCK, gastrin, GIP)
  • Part (a): Clinical correlation: jaundice types (hepatic, obstructive, hemolytic) and pancreatic insufficiency disorders relevant to Indian population
  • Part (b): Mechanism of oxidative phosphorylation: ETC complexes I-IV, proton gradient, ATP synthase (F0F1), chemiosmotic theory; P/O ratio, sites of ATP synthesis; tissue-specific variations (brown adipose tissue uncoupling, muscle fiber types)
  • Part (b): Integration with cellular metabolism: NADH/FADH2 shuttle systems (malate-aspartate, glycerol-3-phosphate), role in meeting high ATP demands of neural and cardiac tissues
  • Part (c): Eye organogenesis: optic vesicle evagination from diencephalon, optic cup formation (double-layered structure), lens placode induction, differentiation of neural retina (rods, cones) and pigmented retina; cornea, sclera, choroid origins from mesenchyme; vitreous humor development
  • Part (c): Critical developmental events: Pax6, Rx, Six3 gene expression; optic fissure closure and consequences of failure (coloboma); Indian relevance: prevalence of congenital eye defects, vitamin A deficiency context

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness22%11Demonstrates precise understanding across all sub-parts: for (a) distinguishes hepatic vs. gall bladder bile storage, pancreatic acinar vs. islet cell functions; for (b) correctly explains chemiosmotic coupling and proton-motive force; for (c) accurately traces optic vesicle→cup→retina lineage with correct germ layer originsShows generally correct concepts with minor errors: conflates bile production with storage, oversimplifies oxidative phosphorylation as 'mitochondrial ATP production', or confuses optic stalk with optic nerve developmentContains significant factual errors: states pancreas produces bile, describes substrate-level phosphorylation as oxidative phosphorylation, or describes eye development without reference to neural ectoderm origin
Diagram / labelling18%9Includes three high-quality diagrams: (a) hepatic lobule with portal triad and pancreatic acinar structure; (b) mitochondrial cristae with ETC complex arrangement and ATP synthase orientation; (c) sequential stages of optic vesicle invagination with lens placode induction—each with precise anatomical labels and developmental arrowsProvides two adequate diagrams with basic labelling, or three diagrams with missing critical labels (e.g., hepatocytes without sinusoids, ETC without complex numbers, optic cup without layers specified)Single diagram or poorly executed sketches; missing essential structures, unlabelled or incorrectly labelled diagrams, or absence of developmental sequence for eye organogenesis
Examples & nomenclature18%9Uses precise terminology throughout: for (a) names specific enzymes (pancreatic lipase, colipase, carboxypeptidases), hormones (secretin, CCK, GIP) and receptors (CCK-A, CCK-B); for (b) cites inhibitors (rotenone, cyanide, oligomycin) and uncouplers (DNP, thermogenin); for (c) identifies master regulatory genes (Pax6, Rx, Six3) and cites Indian studies on congenital eye defectsUses general terminology with some specific names: mentions 'bile salts' without specific types, 'ETC complexes' without naming inhibitors, or 'embryonic layers' without gene namesVague or incorrect terminology: 'digestive juices,' 'energy production,' 'eye formation' without developmental stages; misspelled or confused nomenclature throughout
Process explanation22%11Explains dynamic processes with mechanistic clarity: for (a) cephalic-gastric-intestinal phase integration with neurohormonal feedback loops; for (b) proton gradient establishment, chemiosmotic coupling, and rotational catalysis in ATP synthase; for (c) inductive tissue interactions (optic vesicle-lens placode reciprocity) with temporal sequencingDescribes processes in static terms: lists secretions without regulatory integration, states 'protons move' without gradient explanation, or describes eye structures without developmental sequenceFragmented or confused process description: muddles neural and hormonal regulation, describes oxidative phosphorylation as simple 'oxygen use,' or presents eye structures without developmental origin
Evolutionary / applied context20%10Integrates evolutionary and applied dimensions: for (a) evolutionary origin of hepato-pancreatic diverticulum in vertebrates; clinical—Indian burden of hepatitis, pancreatic cancer, diabetes; for (b) evolutionary conservation of ETC across domains; applied—mitochondrial diseases, role in ischemia-reperfusion injury; for (c) Pax6 conservation across eye types (camera vs. compound); applied—congenital defects, stem cell therapy for retinal degenerationBrief mention of clinical relevance without depth: notes diabetes or jaundice, mentions mitochondrial diseases generically, or states eye defects without mechanistic link to developmentAbsent or superficial context: no evolutionary perspective, no Indian health relevance, or purely descriptive treatment without application to human welfare or biological understanding

Practice this exact question

Write your answer, then get a detailed evaluation from our AI trained on UPSC's answer-writing standards. Free first evaluation — no signup needed to start.

Evaluate my answer →

More from Zoology 2024 Paper II