IAS UPSC (CSE) Mains 2001: Botany

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Section A

  1. Answer any three of the following in not more than 200 words each 20 × 3 = 60

    1. Distinguish between bacteriophages and plasmids. Give their molecular structure. How are plasmids useful in genetic engineering?

    2. Discuss the role of pigmentation and reserved food in the classification of algae.

    3. How does a parasite recognize its host? Describe the molecular basis of host-parasite relationship.

    4. Describe the structure and evolutionary significance of Rhynia.

  2. Answer the following questions

    1. Describe the mode of sexual reproduction in yeast.

    2. Describe the role of microbes in medicine industry. 30 × 2 = 60

  3. Discuss the evolutionary trends of saprophytes in Bryophytes. 60

  4. What is heterotrichous habit in Algae? Discuss its role in the evolution of terrestrial habit. 60

Section B

  1. Answer any three of the following in not more than 200 words each: 20 × 3 = 60

    1. Jurassic was the best age of Gymnosperms. Discuss.

    2. Describe the role of embryology in classification of angiosperms.

    3. Describe the detailed structure of pollen wall. How has palynology helped in forensic science?

    4. What are the primitive and advanced characters of flower used in driving their phylogeny?

  2. What is double fertilization? In the light of recent studies discuss the mode of fertilization in angiosperms. 60

  3. Answer the following questions

    1. How are somatic hybrids obtained?

    2. Ovule bearing organ of Pinus is a highly reduced shoot in the axil of bract. Discuss. 30 × 2 = 60

  4. Give important flower characters of the following families. Give economics importance of three plants from each family. 15 × 4 = 60

    1. Apiaceae

    2. Rubiaceae

    3. Arecaceae

    4. Brassicaceae


Section A

  1. Answer any three of the following. Each part should be answered in not more than 200 words: 20 × 3 = 60

    1. With suitable diagrams, critically examine the various models of membranes systems in eukaryotic cells and state which one is the most suitable to explain the E. M. Structure and functions of the system.

    2. Give an account of linkage and crossing-over method for gene mapping.

    3. Describe the techniques of gene transfer to produce transgenic plants. Add a critical note on the importance of genetic engineering with special reference to the Indian agriculture.

    4. Explain the concept of ‘standard error’ and comment on its application in various research programmes.

  2. Present an account of extra-chromosomal inheritance, and examine its significance with respect to growth and development of a plant. 60

  3. Discuss the genetic and physiological control of sex determination in plants. Is it possible to modify the genetically determined sex by physiological factors? Substantiate your answer. 60

  4. Critically examine the following alternatives and substantiate with reasons which of the two is preferable: 20 × 3 = 60

    1. Role of RNA in origin and evolution of life on earth versus extra-terrestrial origin and evolution of life.

    2. Gene and genome mapping for selective cloning versus cloning without any restriction.

    3. Mutation for breeding versus protoplast fusion for crop improvement.

Section B

  1. Answer any three of the following. Each part should be answered in not more than 200 words: 20 × 3 = 60

    1. With the help of diagrams, bring out the differences in electron transport mechanism in cyclic and non-cyclic photophosphorylation and explain why the Latter is superior to the former.

    2. Describe the structural peculiarities of enzymes & explain their mode of action in metabolism, growth and development.

    3. The tropical countries are very rich in biodiversity as compared to the temperate countries. Substantiate the statement. Describe methods to conserve biodiversity.

    4. Explain the phenomena of food chain, biomagnifications and ecological pyramids in terms of maintaining ecological equilibrium or otherwise.

  2. Give concise answers to the following: 20 × 3 = 60

    1. Point out the various sources of environmental pollution and suggest suitable remedial measures.

    2. Enumerate the causes of seed dormancy and suggest methods to overcome them. Comment on the probable selective advantages of seed dormancy in the course of evolution.

    3. Give diagrammatic representations of any five biogeochemical cycles showing the direction of energy flow.

  3. Explain the concepts of photoperiodism and verbalization. What is meant by critical photochemical requirement for plait growth and development? In this background re-examine thphotoperiodic classification of plants. 60

  4. Compare C3 and C4 plants from the point of view of metabolic efficiency and total productivity. 60

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