Botany 2024 Paper II 50 marks 150 words Compulsory Write short notes

Q5

Write short notes on the following in about 150 words each : 10×5=50 (a) Explain what is secondary active transport. Discuss its importance in ion acquisition in plants. 10 (b) Discuss what is GOGAT ? Comment on its catalytic function. 10 (c) Regulation of seed dormancy and germination by phytohormones. 10 (d) Metallophytes and their practical importance. 10 (e) Invasive alien species and their impact on biodiversity. 10

हिंदी में प्रश्न पढ़ें

निम्नलिखित में से प्रत्येक पर लगभग 150 शब्दों में संक्षिप्त टिप्पणियाँ लिखिए : 10×5=50 (a) द्वितीयक सक्रिय परिवहन क्या है, समझाइए । पौधों में इसके द्वारा आयन अर्जन के महत्व पर चर्चा कीजिए । 10 (b) गोगेट (GOGAT) क्या है चर्चा कीजिए । इसकी उत्प्रेरक अभिक्रिया पर टिप्पणी कीजिए । 10 (c) पादप हार्मोन्स का बीज प्रसुप्ति तथा अंकुरण में विनियमन । 10 (d) मेटलोफाइट्स तथा उनकी प्रायोगिक उपयोगिता । 10 (e) आक्रामक विदेशी प्रजातियाँ तथा जैव विविधता पर उनके प्रभाव । 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.

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 'write short notes' demands concise, information-dense responses for each sub-part. Allocate approximately 30 words/2 minutes per sub-part (150 words × 5 = 750 total, but exam time constraints suggest ~25-30 minutes total). Structure each note with: (1) precise definition, (2) mechanism/process, (3) significance/application. For (a) emphasize symport/antiport mechanisms; (b) distinguish NADH-GOGAT vs Fd-GOGAT; (c) balance ABA/GA antagonism; (d) cite Indian metallophytes like Rinorea bengalensis; (e) mention Lantana camara or Parthenium hysterophorus impacts.

Key points expected

  • (a) Secondary active transport: Definition using electrochemical gradient; symport (e.g., H+/NO3−) and antiport mechanisms; role in root ion acquisition against concentration gradients; proton-motive force linkage
  • (b) GOGAT: Full form (glutamate synthase); two isoforms (NADH-GOGAT in plastids, Fd-GOGAT in chloroplasts); catalytic function converting GSA + glutamate to 2 glutamate; GS-GOGAT cycle significance
  • (c) Phytohormone regulation: ABA maintains dormancy (ABI3/ABI5 transcription factors); GA breaks dormancy via DELLA protein degradation; ethylene and brassinosteroids; hormone cross-talk and environmental integration
  • (d) Metallophytes: Definition (hyperaccumulators vs excluders); Indian examples (Rinorea bengalensis for Ni, Pteris vittata for As); phytoremediation, phytomining, and biomonitoring applications
  • (e) Invasive species: Definition (IUCN criteria); Indian examples (Lantana camara, Parthenium hysterophorus, Eichhornia crassipes); impacts on native flora, ecosystem services, hybridization, and economic costs

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Demonstrates precise understanding across all five sub-parts: correctly distinguishes primary vs secondary active transport (a); identifies both GOGAT isoforms and their cofactors (b); accurately describes hormone signaling pathways including DELLA and ABI proteins (c); correctly classifies metallophyte types (d); applies IUCN definition of invasive species (e). No conceptual errors.Generally correct definitions with minor inaccuracies—e.g., conflates GOGAT with GS, vague on hormone mechanisms, or imprecise metallophyte classification. Some sub-parts show gaps in mechanistic understanding.Major conceptual errors: describes primary active transport as secondary (a), confuses GOGAT with glutamate dehydrogenase (b), reverses ABA/GA roles (c), fails to distinguish hyperaccumulators from excluders (d), or conflates alien with invasive species (e).
Diagram / labelling15%7.5Includes at least 2-3 well-executed diagrams: symport/antiport schematic for (a), GS-GOGAT cycle for (b), or hormone interaction model for (c). Diagrams are properly labelled with membrane polarity, organelle identification, and directional arrows. Enhances clarity beyond text.One diagram present but incomplete labelling, or diagrams mentioned but not drawn. Alternatively, all sub-parts described textually without visual aids but with reasonable clarity.No diagrams where essential (especially for transport mechanisms and biochemical pathways); or diagrams drawn with fundamental errors (wrong membrane orientation, missing proton gradients, incorrect cofactor placement).
Examples & nomenclature20%10Provides specific, current nomenclature: cites SLC transporter families where relevant (a), specifies Fd-GOGAT vs NADH-GOGAT gene names (b), names specific hormone mutants (abi1, ga1) (c), gives Indian metallophyte species with metal specificity (d), and cites specific invasive species with documented impacts in India (e).Generic examples or outdated nomenclature; mentions 'some plants' or 'certain species' without specificity. Correct family-level identification but missing species names for Indian context.No examples provided; or factually wrong examples (e.g., citing C3 plants as metallophytes without basis, confusing invasive with endemic species, wrong metal-plant associations).
Process explanation20%10Clear stepwise mechanistic explanations: proton gradient coupling to ion movement (a), electron flow in GOGAT catalysis (b), signal transduction cascade from hormone perception to gene expression (c), metal uptake-sequestration-export pathways (d), invasion stages from introduction to impact (e). Uses appropriate technical vocabulary.Describes processes in general terms without clear sequence; some steps missing or conflated. Technical vocabulary present but not precisely applied to mechanisms.Descriptive rather than explanatory; no mechanistic detail; processes described as 'happens' or 'occurs' without causal explanation; confuses cause and effect in pathways.
Application / ecology20%10Strong ecological and applied context: for (a) links to salinity stress adaptation; (b) connects to nitrogen use efficiency in agriculture; (c) discusses pre-harvest sprouting control; (d) details phytoremediation of Indian contaminated sites (e.g., Zawar mines); (e) quantifies biodiversity loss or economic impact in India (e.g., Parthenium in agriculture).Mentions applications superficially without specific context; generic statements about 'agricultural importance' or 'environmental concern' without elaboration or Indian relevance.No application or ecological context provided; or completely misidentifies practical relevance (e.g., suggesting GOGAT for herbicide target, or metallophytes for food crops).

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