Botany 2023 Paper I 50 marks 150 words Compulsory Enumerate

Q5

Answer the following questions in about 150 words each: (a) Alphonse de Candolle classified plants of economic importance into various classes. List these classes and state two examples from each. (10 marks) (b) What are the anatomical differences of the bundle sheath and mesophyll cells between C₃ and C₄ plants? (10 marks) (c) Give an account of different types of trichomes found in modern angiosperms. Write a brief note on the systematic value of trichomes. (10 marks) (d) Discuss the classification of vegetable fibers (excluding wood fibers) according to their botanical origin and give examples. (10 marks) (e) How is the isolation of single cells done from intact plant organs and how is the viability of single cells assessed? (10 marks)

हिंदी में प्रश्न पढ़ें

निम्नलिखित में से प्रत्येक प्रश्न का उत्तर लगभग 150 शब्दों में दीजिए : (a) अल्फोंज डे कंडोल ने आर्थिक महत्व के पौधों को विभिन्न वर्गों में विभाजित किया। इन वर्गों की सूची बनाइए और प्रत्येक वर्ग में से दो उदाहरण दीजिए। (10 अंक) (b) C₃ और C₄ पौधों की पुलाच्छद और पर्णमध्योतक कोशिकाओं में शारीरिक विभिन्नताएँ क्या हैं? (10 अंक) (c) आधुनिक आवृतबीजी पौधों में पाए जाने वाले विभिन्न त्वचारोमों का एक विवरण दीजिए। त्वचारोमों के वर्गीकरणी महत्व पर एक संक्षिप्त टिप्पणी लिखिए। (10 अंक) (d) वनस्पति तंतुओं (लकड़ी के तंतुओं को छोड़कर) के वर्गीकरण पर, उनकी वानस्पतिक उत्पत्ति के आधार पर चर्चा कीजिए और उदाहरण दीजिए। (10 अंक) (e) अक्षुण्ण पौधे के अंगों में से एकल कोशिका अलगाव कैसे किया जाता है और एकल कोशिकाओं की जीवनक्षमता का आकलन कैसे होता है? (10 अंक)

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Directive word: Enumerate

This question asks you to enumerate. 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 'enumerate' demands systematic listing with precision. Allocate ~30 words per sub-part (150 words total), spending roughly equal time on each since all carry 10 marks. Structure: begin each sub-part with a clear heading, present information in bullet points or numbered lists for clarity, and conclude with a brief integrative statement where applicable. Prioritize accuracy of names and classifications over elaboration.

Key points expected

  • (a) Candolle's 12 classes: cereals, legumes, starches, sugars, fruits, oils, textiles, dyes, tannins, medicinal, timber, miscellaneous—with two Indian/world examples each (e.g., Oryza sativa, Triticum aestivum for cereals)
  • (b) C₃ vs C₄ bundle sheath: C₃ has thin-walled, non-chlorophyllous BS with no Kranz; C₄ has thick-walled, chlorophyllous BS with large centrifugal chloroplasts and Kranz anatomy; mesophyll differences in chloroplast type and arrangement
  • (c) Trichome types: glandular (secretory) vs non-glandular; unicellular vs multicellular; branched vs unbranched; covering vs stinging; systematic value in family-level identification (e.g., Labiatae, Solanaceae)
  • (d) Vegetable fiber classification: seed fibers (cotton, kapok), bast fibers (jute, flax, hemp), leaf fibers (sisal, abaca, pineapple), fruit fibers (coir); all with botanical names and uses
  • (e) Single cell isolation: mechanical (maceration, homogenization) vs enzymatic (cellulase, pectinase, macerozyme); viability by Evans blue exclusion, FDA, TTC reduction, or plating efficiency

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5All botanical concepts accurate: Candolle's exact 12 classes with correct examples; precise C₃/C₄ anatomical distinctions including chloroplast type and Kranz presence; trichome classification reflects modern angiosperm morphology; fiber origins botanically correct; isolation methods technically sound with correct enzyme namesMost concepts correct but minor errors: 10-11 Candolle classes, some C₃/C₄ confusion on chloroplast location, incomplete trichome typology, mixed fiber origins, or vague on enzymatic vs mechanical distinctionMajor conceptual errors: wrong number of Candolle classes, fundamental misunderstanding of Kranz anatomy, conflating trichome types with other epidermal structures, confusing fiber types, or describing tissue culture instead of single cell isolation
Diagram / labelling10%5Clear, labeled diagrams for C₃ and C₄ leaf anatomy showing Kranz arrangement, chloroplast positions, and vascular bundle organization; trichome types sketched with structural details; neat presentation despite word limitBasic diagrams present but incomplete labeling or missing key features like chloroplast type distinction; rough sketches without proper orientationNo diagrams where essential (especially for C₃/C₄), or diagrams with major structural errors that misrepresent anatomy; diagrams of wrong structures
Examples & nomenclature25%12.5All examples with correct binomials: Indian examples prioritized (Oryza, Cajanus, Saccharum, Gossypium, Cocos, Corchorus, Linum, Cannabis, Agave, Ananas); fiber sources botanically precise; enzyme names correct (Cellulase 'Onozuka', Macerozyme R-10)Most examples correct but some common names instead of binomials, or minor spelling errors in scientific names; missing Indian relevance in some partsWrong examples for categories (e.g., bamboo as bast fiber), no binomials, or invented names; examples do not match the classification given
Process explanation20%10Clear sequential explanation of enzymatic maceration (surface sterilization → enzyme treatment → gentle agation → filtration → centrifugation); viability assays explained with principle (membrane integrity, esterase activity, respiratory activity); mechanical methods distinguished from enzymaticProcess described but steps unclear or out of order; viability methods listed without explaining the principle; conflation of protoplast isolation with single cell isolationNo clear process described; confused methodology; viability assessment missing or described incorrectly (e.g., confusing with seed viability tests)
Application / ecology20%10Links to practical applications: C₄ anatomy for crop improvement and climate resilience; trichome systematic value for chemotaxonomy and defense; fiber classification relevance to Indian jute/coindustry; single cell techniques for somatic hybridization, mutant selection, and genetic engineering; mentions C₄ crops like maize, sorghum, millets for Indian agricultureSome application mentioned but superficial; ecological significance of trichomes noted briefly; limited connection to Indian economic botany or biotechnologyNo application or ecological context provided; purely descriptive without linking to crop improvement, industry, or research relevance

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