UPSC Botany 2022 — Paper II

Framework: Botany, Paper 2. (a) write short notes: define > 3-4 key features > one example > one-line significance | (b) write short notes: define > 3-4 key features > one example > one-line significance | (c) write short notes: define > 3-4 key features > one example > one-line significance | (d) write short notes: define > 3-4 key features > one example > one-line significance | (e) write short notes: define > 3-4 key features > one example > one-line significance Full marks: Precise definitions, accurate structures, clear processes, and relevant examples for all parts.

• Identify mitochondria and chloroplasts as the primary examples
• Mention presence of their own circular DNA (mtDNA/chloroplast DNA)
• Note presence of 70S ribosomes for protein synthesis
• Explain the endosymbiotic origin (bacterial ancestry)
• Credit Nilsson-Ehle and define polygenic (quantitative) inheritance
• Wheat kernel colour experiment with 1:4:6:4:1 (15:1) F2 for two genes
• Additive, equal and cumulative effect of each contributing allele
• Continuous variation modified by environment
• Describe single membrane structure and matrix enzymes
• Mention catalase and oxidase enzymes
• Explain role in beta-oxidation of fatty acids
• Note function in photorespiration (glycolate metabolism)
• Identify primary wall (cellulose, hemicellulose, pectin)
• Mention secondary wall (lignin, suberin) in woody plants
• Explain middle lamella (pectin) between adjacent cells
• Note function in support, protection, and turgor maintenance
• Describe DNA extraction and restriction enzyme digestion
• Mention gel electrophoresis for separation
• Explain transfer to nitrocellulose membrane (blotting)
• Note hybridization with labeled probe for detection

Framework: null. (a) discuss: intro > 3-4 dimensions > example > balanced close | (b(i)) describe: define > structure or process in order > labelled diagram > significance | (b(ii)) describe: define > structure or process in order > labelled diagram > significance | (c) calculate: given > formula > substitution > result with units > interpretation Full marks: Comprehensive, accurate, and well-structured answers with correct calculations and diagrams.

• Define passive transport (diffusion, osmosis)
• Define active transport (pump mechanism)
• Describe facilitated diffusion via carrier proteins
• Mention bulk transport (endocytosis/exocytosis)
• Define B-chromosomes as supernumerary chromosomes
• Note they are not essential for viability
• Mention they are smaller than A-chromosomes
• Describe their irregular segregation pattern
• Mention their role in evolutionary studies
• Note their use as genetic markers
• Mention potential effects on phenotype
• State the null hypothesis (H0)
• Calculate expected values (798 green, 266 yellow from N = 1064)
• Compute Chi-square value (approx 0.61)
• Compare with critical value (3.84) and accept H0 (fits 3:1)

Framework: null. (a) highlight: name the salient points > one line of substance each > close | (b) explain: definition/context > points in order > small example > short close | (c) discuss: intro > 3-4 dimensions > example > balanced close Full marks: Precise definitions, clear mechanisms, specific examples, and well-structured arguments.

• Precise definition of organic evolution
• Mechanism: Natural selection
• Mechanism: Mutation and recombination
• Mechanism: Genetic drift and gene flow
• Definition of incomplete dominance
• Example: *Mirabilis jalapa* or *Antirrhinum majus*
• Genotypic and phenotypic ratios (1:2:1)
• Significance: Blending vs particulate inheritance

Framework: Botany Paper 2: Define > Structure/Process > Labelled Diagram > Significance. (a(i)) discuss: intro > 3-4 dimensions > example > balanced close | (a(ii)) discuss: intro > 3-4 dimensions > example > balanced close | (b(i)) describe: define > structure or process in order > labelled diagram > significance | (b(ii)) describe: define > structure or process in order > labelled diagram > significance | (c(i)) explain: definition/context > points in order > small example > short close | (c(ii)) explain: definition/context > points in order > small example > short close Full marks: Comprehensive, accurate, and well-structured answers with labelled diagrams and specific examples.

• Define male sterility (MS) and its types (cytoplasmic/nuclear)
• Explain MS as a tool to prevent self-pollination
• Link MS to the production of hybrid seeds
• Mention the need for a restorer gene (Rf) for fertility restoration
• Define the Barnase (toxin) and Barstar (antitoxin) system
• Explain the mechanism: Barnase is an RNase that destroys tapetal RNA, Barstar inhibits Barnase
• Barnase under a tapetum-specific promoter in the female (male-sterile) parent
• Barstar in the male (pollinator) parent restores fertility in the F1
• Define DNA sequencing
• Describe the Sanger method (chain termination) steps
• Mention the use of dideoxynucleotides (ddNTPs)
• Explain the separation of fragments (electrophoresis)
• Mention use in genetic mapping
• Mention use in identifying mutations/diseases
• Mention use in evolutionary studies (phylogeny)
• Mention use in forensics or paternity testing
• Define signal transduction
• Explain the process of converting an extracellular signal to an intracellular response
• Mention the key components (receptor, second messengers, effectors)
• Explain the amplification of the signal
• Explain the cAMP pathway (G-protein coupled receptors)
• Explain the calcium ion pathway
• Explain the phosphoinositide pathway (PIP2/PIP3)
• Explain the receptor kinase / MAPK cascade pathway

Framework: Botany Paper 2: Define > Structure/Process > Diagram > Significance. (a) write short notes: define > 3-4 key features > one example > one-line significance | (b) write short notes: define > 3-4 key features > one example > one-line significance | (c) write short notes: define > 3-4 key features > one example > one-line significance | (d) write short notes: define > 3-4 key features > one example > one-line significance | (e) write short notes: define > 3-4 key features > one example > one-line significance Full marks: All parts: precise definitions, 3-4 key features, one example, one-line significance, labelled diagrams where applicable.

• Define mineral deficiency
• List 3-4 specific symptoms (e.g., chlorosis, necrosis)
• Link symptoms to specific minerals (e.g., N, P, K)
• One-line significance for crop health
• Define RAPD PCR (Random Amplified Polymorphic DNA)
• List 2-3 strengths (e.g., no prior sequence needed)
• List 2-3 weaknesses (e.g., dominant markers)
• One application (e.g., fingerprinting, mapping)
• Define photophosphorylation
• Describe light-dependent reactions
• Distinguish cyclic and non-cyclic photophosphorylation
• Significance for ATP production
• Define endangered plant species
• List 3-4 key features (e.g., habitat loss, overexploitation)
• One example of endangered species
• One-line significance for conservation
• Define phytoremediation
• Describe process (e.g., phytoextraction, phytodegradation)
• One example of phytoremediation
• One-line significance for environmental cleanup

Framework: null. (a(i)) compare: paired headings or table > key differences > significance > conclusion | (a(ii)) describe: define > structure or process in order > labelled diagram > significance | (b(i)) define: precise definition > the distinguishing feature > one example | (b(ii)) discuss: intro > 3-4 dimensions > example > balanced close | (c(i)) define: precise definition > the distinguishing feature > one example | (c(ii)) describe: define > structure or process in order > labelled diagram > significance Full marks: Comprehensive, accurate, with labelled diagrams and specific examples; covers all required points with depth.

• Enzymes are proteins; coenzymes are non-protein organic molecules
• Enzymes are specific; coenzymes are non-specific
• Enzymes are heat labile; coenzymes are heat stable
• Enzymes are not consumed; coenzymes are regenerated
• Enzyme mechanism: Lock and key / Induced fit model
• Enzyme mechanism: Transition state stabilization
• Coenzyme mechanism: Electron/proton transfer
• Coenzyme mechanism: Group transfer (e.g., acyl, methyl)
• Not essential for primary growth/development
• Produced in specific tissues or stages
• Distinct from primary metabolites (sugars, amino acids)
• Defense against herbivores and pathogens
• UV protection (e.g., flavonoids)
• Pollinator attraction (e.g., pigments, scents)
• Allelopathy or competition
• Vascular tissue for translocation of organic nutrients
• Composed of sieve tubes, companion cells, phloem parenchyma
• Functions in long-distance transport of sugars
• Pressure flow hypothesis (Münch)
• Active transport hypothesis
• Cytoplasmic streaming hypothesis
• Pressure gradient and bulk flow mechanism

Framework: UPSC Botany Paper 2. (a(i)) describe: define > structure or process in order > labelled diagram > significance | (a(ii)) describe: define > structure or process in order > labelled diagram > significance | (b(i)) discuss: intro > 3-4 dimensions > example > balanced close | (b(ii)) discuss: intro > 3-4 dimensions > example > balanced close | (c(i)) describe: define > structure or process in order > labelled diagram > significance | (c(ii)) describe: define > structure or process in order > labelled diagram > significance Full marks: Precise definitions, correct statutory names, and clear stepwise processes.

• Conservation of biological diversity
• Sustainable use of components
• Fair and equitable sharing of benefits
• Biological Diversity Act, 2002
• National Biodiversity Authority (NBA)
• State Biodiversity Boards (SBBs)
• Nudation and invasion (pioneer species)
• Competition, coaction and reaction
• Stabilization and climax community
• Monoclimax theory (Clements)
• Polyclimax theory (Tansley)
• Climax-pattern hypothesis (Whittaker)
• Weathering of rocks (lithosphere)
• Uptake by plants and transfer to animals (biosphere)
• Sedimentation and return to lithosphere
• Use of phosphate fertilizers
• Eutrophication of water bodies
• Mining of phosphate rocks

Framework: null. (a) define: precise definition > the distinguishing feature > one example | (b(i)) explain: definition/context > points in order > small example > short close | (b(ii)) comment: context > arguments both sides > judgment > close | (c(i)) describe: define > structure or process in order > labelled diagram > significance | (c(ii)) highlight: name the salient points > one line of substance each > close Full marks: Comprehensive, accurate, and well-structured answers with all required elements and bonus points.

• Precise definition of photoperiodism and florigen
• Mechanism of response in short day plants
• Mechanism of response in long day plants
• Suitable examples for both plant types
• Identification of major greenhouse gases
• Mechanism of heat trapping by each gas
• Contribution of each gas to global warming
• Stepwise explanation of the process
• List of adverse effects of global warming
• Mitigation strategies to reduce global warming
• Balanced judgment on effectiveness of strategies
• India-specific impact or action (e.g., NDC, NAPCC)
• Identification of major phytogeographical regions
• Characteristics of each region
• Labelled map or diagram of regions
• Significance of each region
• Identification of key environmental factors
• Explanation of how each factor influences species
• One line of substance for each factor
• Link factors to specific regions