IAS Mains Botany Papers 1989

IAS Mains Botany 1989


Section A

  1. Answer any three of the following questions. Answer to Parts (b) (c), and (d) should not exceed 200 words for each:

    1. Write briefly about the following:

      1. A blue-green alga which may by used as food

      2. A bacterium causing plant tumour

      3. A fungus producing antifungal antibiotic

      4. A fern without circinate vernation

      5. A grmnosperm where male cones are found in groups

    2. Distinguish between ‘antibody’ and ‘complement’ What roles do they play in immunological reactions?

    3. Compare the photosynthetic apparatus in the liver-worts and true mosses.

    4. Distinguish between ‘lytic’ and ‘temperate’ life-cycles of viruses with suitable examples.

  2. Answer the following questions

    1. Distinguish between ‘specific’ and ‘nonspecific’ toxins produced by phytopathogens. Discuss the role in disease and mechanism of action of one of each type.

    2. Comment briefly on any two of the following:

      1. role of phytoalexin in disease resistance of plants

      2. Sex hormones of fungi

      3. Infestation of stored grains by fungi and the possible health hazard

  3. Answer the following questions

    1. give an account of asexual and sexual reproduction of Chlamydomonas. What light does it throw on the origin of sex in plants?

    2. Characterize jungermanialses, justify their position in the hepaticopsida.

  4. Answer the following questions

    1. Give a brief outline of the anatomy of Equisetum. What structural features of Equisetum indicate adaptations to xeric and aquatic environment?

    2. Comment briefly on any three of the following:

      1. Radiometric dating of fossils

      2. Angiospermic characters of Gnetum

      3. totipotency in plants

Section B

  1. Answer any three of the following questions:

    1. What is paleontology and what are its applications?

    2. How many nuclei are ultimately formed in germinated angiosperm pollen? What is the fate of each of these nuclei?

    3. What are the underlying principles for the distribution of mechanical tissues in plants?

    4. What are protoplasts? How are they obtained on a large scale? What are various methods by which protoplasts can be used for crop improvement?

  2. Answer the following questions

    1. Describe the post-fertilization changes that take place in a typical dicotyledonous ovule leading to the formation of seed.

    2. On the basis of the structure of reproductive organs only, how would your

  3. Answer the following questions

    1. discuss the differences between the systems of classification of Engler and Hutchinson. Which of these system do you consider more phylogenetic? Give reasons.

    2. Distinguish between any three of the following pairs:

      1. Actinostele and Atactostele

      2. Bast fibres and Wood fibres

      3. Mesogenous stoata and Perigenous stomata

      4. Protophloem and Metaphloem

  4. Answer the following questions

    1. Place the following genera to their respective families and indicate their economic importance:

      1. Helianthus

      2. Digitalis

      3. Atropa

      4. Vanilla

    2. Distinguish between:

      1. Ring porous and Diffuse porous wood

      2. Solid carpel and Valve carpel

      3. Alfa-taxonomy and Mega-taxonomy

      4. Caryopsis and Achene.


Section A

  1. Answer any three of the following in not more than 200 words for each part:

    1. Critically evaluate the role of his tones as genetic repressors in view of recent evidences.

    2. Discuss the similarities between mitochondrion and chloroplast suggesting their prokaryotic orgin.

    3. What are liposomes? Explain their functions and their potential in applied research.

    4. What is genetic engineering? What are its prospects?

  2. Answer the following questions

    1. What are mutations? Comment upon their significance in evolution and for crop improvement. What are the difficulties in studying mutation rate?

    2. Discuss the views on species concept and the role of isolating mechanisms in evolution.

  3. Explain briefly the methodology for construction of recombinant DNA molecules containing eukaryote DNA fragment. Why do problems arise in the expression of eukaryotic genes to produce functional proteins in such a system? What are the achievements through this technique so far and its prospects in future?

  4. Answer any two of the following:

    1. Due to the occurrence of double cross-avers, it is possible to determine the gene order without actually mapping the genes, in a three-point cross. Explain the methodology of this technique. Why do double cross-over occur more rarely than expected?

    2. Explain the mechanism of semi-discontinuous DNA replication in the lagging strand, stressing the role of polymerases.

    3. What is meant by co-linearity of nucleotide and amino acid sequences? Explain briefly the various experimental evidences that support it. What is the present status of colinerity bypothesis in view of recent discoveries in eukaryotes?

Section B

  1. Answer any three of the following in not more than 200 words for each part:

    1. What is Warburg effect? Explain it in terms of the activity of RUBISCO under different conditions.

    2. Describe florigen concept.

    3. What is the significance of pentose phosphate pathway? How does it differ from calvin's cycle?

    4. Differentiate between ageing and senescence. What is the biological significance of senescence is plants?

  2. Explain the biochemistry of nitrogen fixation in Rhizobium with particular reference to nitrogenous, its activity, requirement of ATP, biological reluctant and oxygen restriction.

  3. Answer any two of the following:

    1. What is greenhouse effect? How is it caused? Discuss its impact on global climate, environment, forests and productivity of crop plants. Describe briefly the suggestions made to meet this challenge.

    2. Describe the mechanisms of salt-tolerance in plants.

    3. Discuss the applications of growth regulations in agrihrticulture.

  4. Answer the following questions

    1. A barren hill slope in a drought-prone tribal area of Eastern-Central India has to be afforested. Suggest a feasible ecological plan of action for it and give the names of plants for plantation in that area which not only stop soil erosion but also provide economic products to sup-port rural industries.

    2. Describe the morphological nature of the parts of the following plants which yield products of economic importance and give their uses also:

      1. Azadirachta indica

      2. Diospyros melanoxylon

      3. Catharanthus roseus.

    3. Give botanical names of 3 plants used energy plantations.