Zoology 2023 Paper II 50 marks 150 words Compulsory Highlight

Q5

Write your answer in about 150 words for each of the following: (a) Highlight role of various hormones in the regulation of digestive secretions. (10 marks) (b) Describe the balance sheet of ATP production in glycolysis. (10 marks) (c) Write a note on acrosome reaction during fertilization. (10 marks) (d) List different neurotransmitters. Explain the role of specific neurotransmitter across neuromuscular junction. (10 marks) (e) Explain competitive and non-competitive enzyme inhibition. (10 marks)

हिंदी में प्रश्न पढ़ें

निम्नलिखित प्रत्येक के लिए लगभग 150 शब्दों में उत्तर लिखिए: (a) पाचन स्राव के नियमन में विभिन्न हार्मोनों की भूमिका पर प्रकाश डालिए। (10 अंक) (b) ग्लाइकोलाइसिस में ए.टी.पी. उत्पादन के तुलन पत्र (बैलेंस शीट) का वर्णन कीजिए। (10 अंक) (c) निषेचन के दौरान अग्रापिंडक (एक्रोसोम) प्रतिक्रिया पर एक टिप्पणी लिखिए। (10 अंक) (d) विभिन्न तंत्रीप्रेषियों (न्यूरोट्रांसमिटर्स) की सूची बनाएं। तंत्रिकापेशीय संधि (न्यूरोमस्कुलर जंक्शन) पर विशिष्ट तंत्रीप्रेषी की भूमिका की व्याख्या कीजिए। (10 अंक) (e) प्रतिस्पर्धी एवं गैर-प्रतिस्पर्धी प्रकिण्व संदमन की व्याख्या कीजिए। (10 अंक)

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Directive word: Highlight

This question asks you to highlight. 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 'highlight' demands focused emphasis on key regulatory mechanisms across five distinct physiological topics. Allocate approximately 30 words per sub-part (150 words total), spending roughly equal time on each since all carry equal marks. Structure each sub-part as: identification of key components → mechanism → functional significance. No elaborate introduction or conclusion needed; prioritize precision and coverage over depth in any single area.

Key points expected

  • (a) Hormonal regulation: Gastrin (G-cells, gastric acid secretion), Secretin (S-cells, HCO₃⁻ release), CCK (I-cells, enzyme secretion, gallbladder contraction), GIP, Motilin; their target organs and secretory effects
  • (b) Glycolysis ATP balance: 2 ATP invested (hexokinase, PFK-1), 4 ATP produced (substrate-level phosphorylation at phosphoglycerate kinase and pyruvate kinase), net gain 2 ATP per glucose; NADH generation
  • (c) Acrosome reaction: Calcium influx, acrosomal exocytosis, release of hyaluronidase and acrosin, zona pellucida penetration, ZP3/ZP2 receptor interaction, membrane fusion events
  • (d) Neurotransmitters: ACh, catecholamines (NE, E, DA), serotonin, GABA, glutamate, glycine, NO, ATP; ACh at NMJ: quantal release, nicotinic receptor binding, end-plate potential generation, acetylcholinesterase termination
  • (e) Enzyme inhibition: Competitive (reversible, Vmax unchanged, Km increased, structurally similar to substrate, overcome by substrate excess) vs Non-competitive (Vmax decreased, Km unchanged, binds allosteric site, not overcome by substrate)

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Accurately states hormonal targets (gastrin → parietal cells), correct net ATP yield (2 ATP), precise acrosome enzyme names, correct NMJ neurotransmitter (ACh, not others), accurate Vmax/Km relationships for both inhibition typesMinor errors in hormone targets, states 4 ATP gross without net calculation, vague acrosome description, lists neurotransmitters without specifying ACh at NMJ, conflates competitive/non-competitive effectsFundamental errors like stating insulin for digestive secretion, incorrect ATP arithmetic, missing acrosome reaction entirely, wrong neurotransmitter at NMJ, reverses inhibition kinetics
Diagram / labelling15%7.5Includes schematic for (c) acrosome reaction showing inner acrosomal membrane/outer acrosomal membrane fusion, or (d) NMJ with pre/post-synaptic elements; or (e) Lineweaver-Burk plots comparing 1/V vs 1/[S] for both inhibitionsMentions diagrams without drawing, or draws incomplete sketches lacking key labels (acrosomal cap, synaptic cleft, 1/Vmax intercept)No diagrams where clearly applicable; or completely erroneous diagrams showing wrong structures
Examples & nomenclature20%10Uses precise nomenclature: G-cells/S-cells/I-cells, phosphoenolpyruvate, hyaluronidase/acrosin, nicotinic ACh receptor (nAChR), acetylcholinesterase; cites specific inhibitors like malonate for competitive, heavy metals for non-competitiveGeneric terms like 'stomach cells' instead of G-cells, 'sugar breakdown' instead of glycolytic intermediates, 'sperm enzymes' without naming, 'nerve chemical' instead of AChIncorrect nomenclature throughout; invents non-existent hormones or enzymes; confuses acrosome with nucleus
Process explanation25%12.5Clear mechanistic flow: for (a) stimulus-secretion coupling; (b) energy investment vs payoff phases; (c) signal transduction (Ca²⁺→exocytosis→zona penetration); (d) vesicle fusion→quantal release→depolarization; (e) structural basis for binding differencesLists components without explaining sequential mechanisms; describes end results without intermediate steps; static description without dynamic processNo logical sequence; random facts without causal connections; fundamentally wrong mechanism (e.g., acrosome reaction before capacitation)
Evolutionary / applied context15%7.5Brief mention of clinical relevance: Zollinger-Ellison syndrome (gastrinoma) for (a); Warburg effect in cancer for (b); infertility treatments targeting acrosome for (c); myasthenia gravis/Lambert-Eaton for (d); drug design (statins, sulfa drugs) for (e)Vague statement about 'medical importance' without specific disease or application; generic evolutionary conservation comment without elaborationNo applied or evolutionary context; or completely irrelevant applications (e.g., digestive hormones for diabetes management without specificity)

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