Botany 2021 Paper II 50 marks Compulsory Write short notes

Q5

Write short notes on the following : 10×5=50 (a) Alkaloids and their significance 10 (b) Role of growth substances in agri-horticulture 10 (c) Plant indicators 10 (d) Invasive species and their characteristics 10 (e) IUCN Red List Categories 10

हिंदी में प्रश्न पढ़ें

निम्नलिखित पर संक्षिप्त टिप्पणियाँ लिखिए : 10×5=50 (a) एल्केलॉइड्स और उनके महत्व 10 (b) कृषि-बागवानी में वृद्धि पदार्थों की भूमिका 10 (c) पादप सूचक 10 (d) आक्रामक प्रजातियाँ (स्पीशीज़) और उनकी विशेषताएँ 10 (e) आई.यू.सी.एन. लाल सूची श्रेणियाँ 10

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Directive word: Write short notes

This question asks you to write short notes. 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

Write short notes demands concise, information-dense responses for each sub-part without elaborate introductions. Allocate approximately 100-120 words per sub-part (equal marks distribution): (a) define alkaloids with nitrogenous base structure, significance in medicine/defense; (b) categorize auxins, gibberellins, cytokinins, ethylene, ABA with specific agri-horticulture applications; (c) explain bioindicator concept with heavy metal/pollution detection examples; (d) define invasive species, list characteristics (rapid growth, high reproduction, allelopathy, lack of natural enemies); (e) enumerate IUCN categories from Extinct to Least Concern with criteria. Use bullet points or short paragraphs for clarity; no conclusion needed.

Key points expected

  • (a) Alkaloids: nitrogen-containing secondary metabolites; examples (morphine, quinine, nicotine, caffeine); significance in pharmaceuticals, pesticides, plant defense; mention Indian medicinal plants (Rauwolfia, Cinchona, Papaver)
  • (b) Growth substances: five major classes with specific agri-horticulture roles—auxins (rooting, parthenocarpy), gibberellins (seed dormancy breaking, fruit enlargement), cytokinins (tissue culture, delay senescence), ethylene (ripening, abscission), ABA (stress tolerance, stomatal closure)
  • (c) Plant indicators: organisms indicating environmental conditions; examples—lichens (air quality), Eichhornia (water pollution), metallophytes (heavy metal soils); mention Indian examples (Fern species for arsenic, Prosopis for salinity)
  • (d) Invasive species: non-native organisms causing ecological/economic harm; characteristics—high reproductive rate, rapid dispersal, phenotypic plasticity, allelopathy, absence of co-evolved predators; Indian examples (Lantana camara, Parthenium hysterophorus, Eichhornia crassipes)
  • (e) IUCN Red List Categories: hierarchical classification from Extinct (EX), Extinct in Wild (EW), Critically Endangered (CR), Endangered (EN), Vulnerable (VU), Near Threatened (NT), Least Concern (LC); mention criteria A-E for assessment; cite Indian examples in each category

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Precise biochemical definitions: alkaloids as heterocyclic nitrogen compounds; accurate hormone mechanisms (signal transduction for auxins, GA-DELLA protein interaction); correct IUCN category definitions with population thresholds; invasive species distinguished from exotic/nativeBasic definitions correct but confused categories (e.g., mixing IUCN levels) or oversimplified hormone action; minor errors in alkaloid classificationFundamental misconceptions: calling alkaloids proteins, confusing growth promoters/inhibitors, incorrect IUCN hierarchy, equating all exotic species with invasive
Diagram / labelling10%5Includes relevant diagrams: alkaloid biosynthesis pathway (shikimate/terpenoid origin), IUCN Red List category pyramid, or growth substance dose-response curves; neat labelling with chemical structures where appropriateSimple flowcharts or tables substituting for diagrams; adequate but not detailed labellingNo diagrams where expected (especially for IUCN hierarchy or biosynthesis pathways); messy unlabelled sketches
Examples & nomenclature25%12.5Rich Indian examples: for (a) Rauwolfia serpentina (reserpine), Catharanthus roseus (vincristine), Papaver somniferum; for (c) Datura as pollution indicator, Selaginella for humidity; for (d) detailed invasion history of Lantana, Parthenium, Chromolaena; for (e) specific Indian species in each IUCN category (e.g., Gymnocladus assamicus as CR)Common examples only (morphine, quinine, Lantana) without Indian specificity; generic invasive mentions; few IUCN examplesNo examples or incorrect ones; misspelled scientific names; no Indian context; confused examples across sub-parts
Process explanation20%10Clear mechanistic explanations: alkaloid biosynthesis from amino acid precursors (tyrosine, tryptophan, lysine); hormone signal transduction pathways (auxin: TIR1-Aux/IAA-ARF; GA: GID1-DELLA degradation); IUCN assessment criteria (population reduction, geographic range, extinction probability)Descriptive rather than mechanistic; mentions processes without explaining how they work; incomplete pathwaysNo process explanation; lists facts without causal connections; confused or reversed mechanisms
Application / ecology20%10Strong applied focus: for (a) pharmaceutical industry, drug resistance management; for (b) specific protocols (NAA for rooting, ethrel for pineapple flowering, paclobutrazol for mango); for (c) biomonitoring protocols, phytoremediation; for (d) management strategies (biological control using Zygogramma for Parthenium); for (e) conservation prioritization, CITES linkageMentions applications superficially; generic statements without specific protocols or conservation strategiesNo applied dimension; purely theoretical treatment; irrelevant or impractical suggestions

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