IAS Mains Botany Paper 2012

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Section –A

Q.1 Briefly describe the following in not more than 150 words each :

  1. Bipolar and Tetrapolar heterothallism in fungi

  2. Cytoplasmic hybrids

  3. Fungal Toxins

  4. Elaters

  5. Plant quarantines.


  1. Somaclonal variations can be used for variety of crop development. How ? Explain with suitable examples.

  2. Give an account of Ascus development in fungi with suitable examples.

  3. Describe the enzymatic method of isolation of protoplasts taking the example of Carrot.

Q.3 Draw well labelled diagrams of the following :

  1. L. S. of sporophyte of Riccia

  2. L. S. of sporophyte of Funaria

  3. L. S. of strobilus of Selaginella

  4. H.L.S. of Marsilea sporocarp

Q.4 Differentiate between the following :

  1. Polarity and Symmetry

  2. Prions and Viroids

  3. Rust and Smut diseases

  4. Eusporangiate and Laptosporangiate ferns

  5. Downy mildews and Powdery mildews.

Section –B

Q.5 Answer the following in about 150 words each :

  1. Write the botanical names and the families to which the following plants belong :

    1. Flax

    2. Guar

    3. Date Palm

    4. Cocaine

    5. Ginseng

    6. Any timeber plant

  2. Give a brief account of Dwarf shoot in Pinus.

  3. Differentiate between interxylary and intraxylary phloems.

  4. Make a comparison of Androecium in Malvaceae, Asteraceae and Cucurbitaceae.

  5. Give a brief account of polyembryony in Angiosperms.


  1. Compare the female strobili of Pinus and Ephedra.

  2. Compare the development of typical monosporic, bisporic and tetrasporic embryo sacs.

  3. Draw a labelled diagram of L.S. of Ovule of Cycas.

  4. Why is Ginkgo biloba considered as a living fossil ? Explain.


  1. Vavilov’s theory indicates that “a region with the greatest genetic diversity is also the centre of origin of that particular species.” This statement is no longer tenable. Explain with any two examples.

  2. Draw a cross section of a typical anther and label the parts carefully.

  3. “Gymnosperms were perhaps the immediate ancestors of angiosperms.” Substantiate the statement, and also give reasons to disprove the statement.


  1. “Embryology has also played an important role in Taxonomy of angiosperms.” Elaborate the statement with the help of some examples.

  2. Asteraceae is considered as one of the highly evolved families of angiosperms. Give an account of advanced characters in Asteraceae.

  3. Ethnobotany has provided important clues to discovery of modern drugs. Give an account of Ethnobotany taking some suitable examples.

  4. Compare and contrast the floral characters of the three sub-families of Leguminosae.


Section –A


  1. What is ‘RNA world’ and what makes it to be considered as the precursors for the origin and evolution of cellular life ?

  2. How would you distinguish between reverse and suppressor mutations ?

  3. Briefly explain the different pathways takes by secreted proteins.

  4. Give an experimental evidence to demonstrate that DNA is a generic material.

  5. What do you mean by site-specific recombination? Disucss the role of recombinase enzyme in this process.


  1. What do you mean by aneuploidy and what kinds of chromosomal variations are found in aneuploid plants?

  2. What are transposons and how do they cause mutations?

  3. Compare the different types of RNA and protein components found in the ribosomes of prokaryotes and eukaryotes.


  1. Explain the role of cdk and cyclin proteins in the regulation of cell cycle.

  2. Compare the gene expression of lac operon in the presence and absence of its functional regulatory gene.

  3. Describe the chromosomal basis of sex differentiation in plants.

  4. Describe how the discovery of infectious proteins brought a change in the concept of inheritance.


  1. Illustrate the fate of two homologous chromosomes that have undergone unilateral crossing-over.

  2. Explain the importance of DNA-DNA hybridization techniques in the study of biodiversity.

  3. What are gene markers ? Explain their importance in biological studies.

  4. Discuss the use of apomixes in plant breeding.

Section –B


  1. What is superbug? Describe its properties and possible role in bioremediation.

  2. What are ozone-depleting substances and how they cause depletion of ozone layers in stratosphere?

  3. What is characteristic pathway of carbon fixation in tropical grasses and what are the advantages of the pathway?

  4. What makes the leguminous plants to grow under the nitrogen stress condition?

  5. Distinguish between passive and facilitated diffusion.


  1. Explain the process of anaerobic glucose catabolism and mention the mode of ATP generation during the process.

  2. What are the different IUCN threat categories of biodiversity and their implications in conservation?

  3. What is Rubisco, whare is it located and what function does it serve?


  1. Explain the mechanism of chemiosmotic generation of ATP.

  2. What are primers? Explain their role in PCR.

  3. Discuss the ecological significance of nitrifying and denitrifying bacteria associated with biogeochemical cycle.

  4. How is light energy captured in green plants?


  1. Give a brief note on the concept of sustainable development.

  2. What is the principle of blotting? Give an illustrated account of the steps involved in Southern blotting.

  3. What is the ‘hot spot’? Describe the hot spots of India, giving names of few important species.

  4. Explain eco-regulation. Justify plant appearances and disappearances leading to climatic climax.

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