Botany

UPSC Botany 2021 — Paper I

All 8 questions from UPSC Civil Services Mains Botany 2021 Paper I (400 marks total). Every stem reproduced in full, with directive-word analysis, marks, word limits, and answer-approach pointers.

8Questions
400Total marks
2021Year
Paper IPaper

Topics covered

Lichens, prions, Rhizopus, numerical taxonomy, gymnosperm distribution (1)Bacterial genetics, evolution of sex in algae, progymnosperms (1)Wheat diseases, fossil gymnosperms, bryophytes and pteridophytes (1)Algal life cycles, stellar diversity in vascular cryptogams, bioremediation (1)Trichomes, Asteraceae and Orchidaceae, ethnobotany, plant domestication, cellular totipotency (1)Female gametophyte in angiosperms, ethnomedicinal plants, secondary metabolites (1)Economic botany of fibre and gum plants, somatic embryogenesis, protoplast isolation (1)Plant preservation and conservation, micropropagation, androgenic haploids (1)

A

Q1
50M 150w Compulsory describe Lichens, prions, Rhizopus, numerical taxonomy, gymnosperm distribution

Answer the following in about 150 words each: (a) Describe the structure and functions of cyphellae and cephalodia in lichens. (b) What are prions? How are these different from viroids? How are prions transmitted? (c) Explain the structure of sporangiophore and dehiscence of sporangium of Rhizopus. (d) Enumerate the merits and demerits of numerical taxonomy. (e) Briefly discuss the distribution of gymnosperms in India.

हिंदी में पढ़ें

निम्नलिखित में से प्रत्येक का लगभग 150 शब्दों में उत्तर दीजिए : (a) लाइकेन के सिफेली (उपदर्श) व सिफेलोडिया की संरचना एवं कार्य का वर्णन कीजिए। (b) प्रायोन क्या हैं? ये वायरोइड से किस प्रकार भिन्न हैं? प्रायोन किस तरह से प्रसारित होते हैं? (c) राइजोपस के बीजाणुधानीधर की संरचना तथा बीजाणुधानी के स्फुटन का वर्णन कीजिए। (d) संख्याविषयक वर्गीकरण-विज्ञान के गुण व दोषों की परिगणना कीजिए। (e) भारत में अनावृतबीजी के वितरण का संक्षिप्त वर्णन कीजिए।

Answer approach & key points

Framework: UPSC Botany Paper 1. (a) describe: define > structure or process in order > labelled diagram > significance | (b) define: precise definition > the distinguishing feature > one example | (c) explain: definition/context > points in order > small example > short close | (d) enumerate: list the items in order > one line each > no commentary | (e) discuss: intro > 3-4 dimensions > example > balanced close Full marks: Precise definitions, accurate diagrams, specific examples, and clear differentiation.

  • Cyphellae: pores in upper cortex for gas exchange
  • Cephalodia: specialized photobiont colonies (e.g., Nostoc)
  • Cephalodia function: nitrogen fixation
  • Labelled diagram of lichen thallus showing both
  • Prions: misfolded proteins (PrP^Sc), no nucleic acid
  • Viroids: naked ssRNA, no protein coat
  • Transmission: ingestion, iatrogenic, or genetic
  • Disease example (e.g., BSE, CJD)
Q2
50M explain Bacterial genetics, evolution of sex in algae, progymnosperms

(a) Explain conjugation and transformation in bacteria. Write a brief note on their significance. (20 marks) (b) Explain evolution of sex in algae with suitable examples. (20 marks) (c) Describe the concept of progymnosperms with the help of suitable examples. (10 marks)

हिंदी में पढ़ें

(a) जीवाणु में संयुग्मन (कांजुगेशन) व रूपांतरण (ट्रांसफॉर्मेशन) की व्याख्या कीजिए। उनके महत्व पर एक संक्षिप्त टिप्पणी लिखिए। (20 अंक) (b) समुचित उदाहरणों से शैवाल के लिंग-विकास की व्याख्या कीजिए। (20 अंक) (c) समुचित उदाहरणों सहित प्रोजिम्नोस्पर्म की अवधारणा का वर्णन कीजिए। (10 अंक)

Answer approach & key points

Framework: Botany Paper 1: Define > Structure/Process > Labelled Diagram > Significance. (a) explain: definition/context > points in order > small example > short close | (b) explain: definition/context > points in order > small example > short close | (c) describe: definition/context > points in order > small example > short close Full marks: Clear mechanisms, labelled diagrams, specific examples, strong significance

  • Conjugation: F+ x F-, sex pilus, F plasmid
  • Transformation: Naked DNA uptake, competence
  • Isogamy: Chlamydomonas
  • Anisogamy: Oogonium, Antheridium
  • Oogamy: Fucus
  • Progymnosperms: Archaeopteris, Protopteris, Peltandra
  • Transitional group: Ferns to gymnosperms
Q3
50M discuss Wheat diseases, fossil gymnosperms, bryophytes and pteridophytes

(a) Discuss about the names of causal organisms, symptoms, disease cycle and management of loose smut of wheat. What are the differences between rust and smut fungi? (20 marks) (b) Enumerate the salient features of fossil gymnosperms using suitable examples with special reference to Bennettitales and Cordaitales. (20 marks) (c) Give the general characteristics of bryophytes. Enlist the resemblances and differences of bryophytes with pteridophytes. (10 marks)

हिंदी में पढ़ें

(a) गेहूं के रलथ कंड के कारक जीव के नाम, लक्षण, व्याधि चक्र तथा प्रबंधन के बारे में लिखिए। किड़ तथा कंड कवक में क्या अंतर हैं? (20 अंक) (b) बेनरिटाइटेल व कोर्डाइटेल के विशिष्ट संदर्भ में उपयुक्त उदाहरणों का उपयोग करते हुए जीवाश्मी अनावृतबीजी के प्रमुख लक्षणों की गणना कीजिए। (20 अंक) (c) ब्रायोफाइट के सामान्य लक्षण बताइए। ब्रायोफाइट तथा टेरिडोफाइट की समानता व अंतर को सूचीबद्ध कीजिए। (10 अंक)

Answer approach & key points

Framework: UPSC Botany Paper 1. (a) discuss: intro > 3-4 dimensions > example > balanced close | (b) enumerate: list the items in order > one line each > no commentary | (c) describe: define > structure or process in order > labelled diagram > significance Full marks: Comprehensive, accurate, with labelled diagrams and specific examples.

  • Causal organism name (Ustilago tritici) and symptoms
  • Disease cycle and management of loose smut
  • Differences between rust and smut fungi
  • Labelled diagram of loose smut or cycle
  • Features of Bennettitales (e.g., Bennettia)
  • Features of Cordaitales (e.g., Cordaites)
  • General features of fossil gymnosperms
  • Suitable examples for each order
Q4
50M explain Algal life cycles, stellar diversity in vascular cryptogams, bioremediation

(a) Explain with the help of schematic diagrams haplontic, diplontic, isomorphic, heteromorphic and triphasic types of life cycles in algae. Give an example of each type. (20 marks) (b) Describe stellar diversity in vascular cryptogams along with its evolutionary importance. (20 marks) (c) Discuss the applications of microbes in bioremediation of soil and water. (10 marks)

हिंदी में पढ़ें

(a) आरेख चित्रों की सहायता से शैवाल में पाये जाने वाले हैप्लोटिक, डिप्लोटिक, आइसोमॉर्फिक (समरूपी), हेटेरोमॉर्फिक (विषमरूपी) तथा ट्राइफेजिक प्रकार के जीवन-चक्र को समझाइए। सभी प्रकार का एक-एक उदाहरण दीजिए। (20 अंक) (b) संवहनी क्रिप्टोगैम में रंभीय (स्टेलर) विविधता का वर्णन करते हुए इसकी विकासीय महत्ता प्रकट कीजिए। (20 अंक) (c) मृदा एवं जल के जैविक उपचार में जीवाणुओं के उपयोग की विवेचना कीजिए। (10 अंक)

Answer approach & key points

(a) explain: definition/context > points in order > small example > short close | (b) describe: define > structure or process in order > labelled diagram > significance | (c) discuss: intro > 3-4 dimensions > example > balanced close Full marks: Comprehensive, accurate, well-illustrated with clear evolutionary and practical links.

  • Haplontic cycle diagram with example (e.g., *Chlamydomonas*)
  • Diplontic cycle diagram with example (e.g., *Fucus*)
  • Isomorphic alternation of generations diagram (e.g., *Ulva*)
  • Heteromorphic alternation of generations diagram (e.g., *Fucus* or *Laminaria*)
  • Definition of vascular cryptogams (ferns, lycophytes)
  • Description of stelar types (protostele, siphonostele, eustele)
  • Evolutionary significance of stelar complexity
  • Link to adaptation to terrestrial life

B

Q5
50M 150w Compulsory enumerate Trichomes, Asteraceae and Orchidaceae, ethnobotany, plant domestication, cellular totipotency

Answer the following in about 150 words each: (a) Enumerate different kinds of trichomes and explain their taxonomic importance. (b) Discuss the advanced features of Asteraceae and Orchidaceae. (c) Explain the importance of ethnobotany in human welfare. (d) Mention the evolutionary changes that occur during domestication of plants. Also mention its advantages and disadvantages. (e) Discuss the concept of cellular totipotency in higher plants.

हिंदी में पढ़ें

निम्नलिखित में से प्रत्येक का लगभग 150 शब्दों में उत्तर दीजिए : (a) भिन्न प्रकार के त्वचा-रोम का उल्लेख करते हुए उनका वर्गीकीय महत्त्व स्पष्ट कीजिए। (b) एस्टेरेसी एवं ऑर्किडेसी की उन्नत विशेषताओं का वर्णन कीजिए। (c) लोक-वनस्पति-विज्ञान का मानव-कल्याण में महत्त्व को समझाइए। (d) घरेलुकरण के दौरान पादपों में होने वाले विकासमूलक परिवर्तनों का उल्लेख कीजिए। साथ ही इसके लाभ व हानि का भी उल्लेख कीजिए। (e) उच्च पादपों में कोशिकीय प्रशक्यता की संकल्पना की विवेचना कीजिए।

Answer approach & key points

Framework: UPSC Botany Paper 1. (a) enumerate: list the items in order > one line each > no commentary | (b) discuss: intro > 3-4 dimensions > example > balanced close | (c) explain: definition/context > points in order > small example > short close | (d) enumerate: list the items in order > one line each > no commentary | (e) discuss: intro > 3-4 dimensions > example > balanced close Full marks: Precise, specific, with diagrams and examples.

  • Distinguish glandular from non-glandular trichomes
  • Classify non-glandular into simple, branched, stellate, T-shaped
  • Link specific trichome types to taxonomic families
  • Mention function (defense, secretion) as secondary
  • Identify Asteraceae advanced features (syngenesy, cypsela)
  • Identify Orchidaceae advanced features (resupinate, column)
  • Compare floral symmetry (actinomorphic vs zygomorphic)
  • Mention fruit types (achene vs capsule)
Q6
50M describe Female gametophyte in angiosperms, ethnomedicinal plants, secondary metabolites

(a) Describe the development of female gametophyte in angiosperms with the help of suitable illustrations. (20 marks) (b) Give the botanical name, part used and ethnomedicinal importance of any three species each of Fabaceae, Euphorbiaceae and Liliaceae. (20 marks) (c) Define secondary metabolites. Explain their importance in taxonomy. (10 marks)

हिंदी में पढ़ें

(a) आवृत्तबीजी के मादा युग्मकोद्भिद के परिवर्धन का संयुक्त चित्र सहित वर्णन कीजिए। (20 अंक) (b) फेबेसी, युफोर्बिएसी तथा लिलिएसी, प्रत्येक के किन्हीं तीन पादपों का वानस्पतिक नाम, उपयोगी भाग तथा मानवजनित-औषधीय महत्व दीजिए। (20 अंक) (c) द्वितीयक उपापचयज को परिभाषित कीजिए। वर्गीकी में उनके महत्व को स्पष्ट कीजिए। (10 अंक)

Answer approach & key points

Framework: UPSC Botany Paper 1. (a) describe: define > structure or process in order > labelled diagram > significance | (b) highlight: name the salient points > one line of substance each > close | (c) explain: definition/context > points in order > small example > short close Full marks: Comprehensive, accurate, well-structured with labelled diagrams and specific examples.

  • Megaspore mother cell meiosis to tetrad
  • Functional megaspore selection and mitosis
  • Nuclei migration and cell wall formation
  • Mature embryo sac structure (7 cells, 8 nuclei)
  • Three distinct species from Fabaceae
  • Three distinct species from Euphorbiaceae
  • Three distinct species from Liliaceae
  • Correct botanical names (italicised binomials)
Q7
50M describe Economic botany of fibre and gum plants, somatic embryogenesis, protoplast isolation

(a) Describe the economic botany of fibre and gum yielding plants (five species each). (20 marks) (b) Discuss the factors affecting somatic embryogenesis. (20 marks) (c) Describe the method of isolation of protoplast from leaf tissue. (10 marks)

हिंदी में पढ़ें

(a) रेशा व गोंद उत्पादक पादपों (प्रत्येक के पाँच) के आर्थिक वनस्पति-विज्ञान का वर्णन कीजिए। (20 अंक) (b) कायिक भ्रूणजनन को प्रभावित करने वाले घटकों की विवेचना कीजिए। (20 अंक) (c) पर्ण उत्तक से जीवद्रव्यक के अलगाव की विधि का वर्णन कीजिए। (10 अंक)

Answer approach & key points

Framework: UPSC Botany Paper 1. (a) describe: define > structure or process in order > labelled diagram > significance | (b) discuss: intro > 3-4 dimensions > example > balanced close | (c) describe: define > structure or process in order > labelled diagram > significance Full marks: Precise binomials, specific factors, clear method steps, labelled diagrams.

  • Five fibre species with italicized binomials
  • Five gum species with italicized binomials
  • Part yielding fibre or gum for each
  • Economic use or industrial application
  • Hormonal factors (auxin/cytokinin balance)
  • Genetic factors (genotype/embryogenic potential)
  • Culture conditions (media, light, temp)
  • Physiological factors (age, explant type)
Q8
50M compare and contrast Plant preservation and conservation, micropropagation, androgenic haploids

(a) Compare and contrast 'preservation' and 'conservation' of plants. Explain the importance of both in the utilization and management of plant resources. (20 marks) (b) Describe different stages of micropropagation and discuss its advantages over conventional methods of propagation. (20 marks) (c) Explain the technique used in producing androgenic haploids and its applications in agriculture. (10 marks)

हिंदी में पढ़ें

(a) पादपों के 'परिरक्षण' एवं 'संरक्षण' की तुलना एवं विषमता कीजिए। पादप साधनों की उपयोगिता एवं प्रबंधन में दोनों का महत्व समझाइए। (20 अंक) (b) सूक्ष्म-प्रवर्धन की विभिन्न अवस्थाओं का वर्णन कीजिए और परम्परागत प्रवर्धन विधियों की तुलना में इसकी श्रेष्ठता की विवेचना कीजिए। (20 अंक) (c) पुंजनिक अगुणित प्राप्ति की तकनीक एवं कृषि में इसकी उपयोगिता का वर्णन कीजिए। (10 अंक)

Answer approach & key points

(a) compare: paired headings or table > key differences > significance > conclusion | (b) describe: define > structure or process in order > labelled diagram > significance | (c) explain: definition/context > points in order > small example > short close Full marks: Precise definitions, clear distinction between terms, detailed stepwise processes, and specific examples of species or applications.

  • Define preservation (in-situ/ex-situ) vs conservation (sustainable use)
  • Contrast objectives: static protection vs dynamic management
  • Explain importance in utilization of plant resources
  • Explain importance in management of plant resources
  • Define micropropagation (tissue culture)
  • Describe stages: Selection, Initiation, Multiplication, Rooting, Hardening
  • List advantages: rapid multiplication, disease-free plants
  • Compare specifically with conventional methods (seeds/cuttings)

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