Zoology 2022 Paper II 50 marks 150 words Compulsory Draw

Q1

Write your answer in about 150 words for each of the following : 10×5=50 (a) Draw the structure of a microtubule and explain its role in chromosomal movements during cell division. (b) What is mutation? Write a brief note on various types of point mutations. (c) Give schematic organization of cosmid. Why is it preferred over plasmid for gene cloning? (d) Explain Hardy-Weinberg law of equilibrium and mention the factors that upset the equilibrium. (e) Write a note on the theory of natural selection.

हिंदी में प्रश्न पढ़ें

निम्नलिखित प्रत्येक के लिए लगभग 150 शब्दों में अपना उत्तर लिखिए : 10×5=50 (a) एक सूक्ष्म-नलिका की संरचना बनाइए तथा कोशिका विभाजन के दौरान गुणसूत्रों के संचलन में इसकी भूमिका की व्याख्या कीजिए। (b) उत्परिवर्तन क्या है? विभिन्न प्रकार के बिंदु उत्परिवर्तनों पर एक संक्षिप्त टिप्पणी लिखिए। (c) कॉस्मिड का व्यवस्थित संगठन प्रस्तुत कीजिए। जीन क्लोनिंग के लिए प्लाज्मिड के ऊपर इसको वरियता क्यों दी जाती है? (d) हार्डी-विनबर्ग के साम्यावस्था के नियम की व्याख्या कीजिए तथा उन कारकों का उल्लेख कीजिए जो साम्यावस्था को अनियमित करते हैं। (e) प्राकृतिक चयन के सिद्धांत पर एक टिप्पणी लिखिए।

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Directive word: Draw

This question asks you to draw. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.

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How this answer will be evaluated

Approach

Begin with the directive 'draw' for part (a), then 'explain' for mechanisms, 'define' for mutation, 'sketch' for cosmid organization, and 'state' for laws and theories. Allocate approximately 30 words each across five parts (~150 words total), ensuring diagrams for (a) and (c) are drawn first before explanatory text. Structure as: diagram + brief explanation for each part, with no elaborate introduction or conclusion due to severe word constraints.

Key points expected

  • (a) Draw hollow cylindrical microtubule with 13 protofilaments of α/β-tubulin dimers; explain dynamic instability and kinetochore attachment for anaphase chromosome movement
  • (b) Define mutation as heritable DNA change; classify point mutations as transitions, transversions, silent, missense, nonsense, and frameshift with one example each
  • (c) Sketch cosmid with plasmid origin, cos sites, antibiotic resistance marker; explain 35-45 kb insert capacity advantage over plasmids (10 kb limit)
  • (d) State Hardy-Weinberg equation (p² + 2pq + q² = 1); list disrupting factors: mutation, gene flow, genetic drift, natural selection, non-random mating
  • (e) Outline Darwin-Wallace natural selection: variation, heritability, overproduction, differential survival; mention industrial melanism in Biston betularia as Indian example

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness20%10Accurately describes α/β-tubulin heterodimers in (a), correctly defines all mutation types in (b), precisely states cosmid features and H-W equation in (c)-(d), and captures Darwin's mechanism without Lamarckian errors in (e)Minor errors in tubulin structure or mutation classification; incomplete H-W equation or vague natural selection descriptionFundamental misconceptions such as confusing microtubules with microfilaments, misdefining point mutations, or conflating natural selection with inheritance of acquired characters
Diagram / labelling20%10Clear 13-protofilament microtubule cross-section and longitudinal view with labelled α/β-tubulin in (a); neat cosmid map showing cos sites, ori, and selectable marker in (c); essential labels present despite space constraintsDiagrams drawn but missing critical labels (e.g., no protofilament count or unlabeled cos sites); disproportionate space allocationMissing diagrams for (a) or (c), or unrecognizable sketches without any labels; diagrams drawn but no accompanying explanation
Examples & nomenclature20%10Uses specific terms: dynamic instability, kinetochore, transition/transversion, missense/nonsense, cos site, λ phage packaging, p/q allele frequencies; cites Biston betularia or sickle-cell anemiaGeneric examples or partially correct nomenclature; mentions 'point mutation' without subtypes or 'selection' without specifying natural selectionNo specific examples; confuses terminology (e.g., 'plasmid' for 'cosmid', 'mitosis' for 'meiosis', 'evolution' for 'natural selection')
Process explanation20%10Concisely explains depolymerization-driven chromosome movement in (a), molecular basis of each mutation type in (b), in vitro packaging rationale in (c), mathematical derivation logic in (d), and selection mechanism in (e)Lists processes without mechanistic detail; describes 'what' happens without 'how' (e.g., 'chromosomes move' without microtubule dynamics)No process explanation; merely defines terms or states outcomes without causal mechanisms; confused cause-effect relationships
Evolutionary / applied context20%10Links microtubules to cancer chemotherapy targets (taxol), mutations to antibiotic resistance, cosmids to Human Genome Project, H-W to conservation genetics, and natural selection to adaptive radiation in Indian fauna (e.g., Nilgiri langur)Brief mention of applications without elaboration; generic statements like 'used in research' or 'important in evolution'No applied or evolutionary context; treats all parts as purely theoretical with no connection to biotechnology, medicine, or biodiversity

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