MAHATMA GANDHI UNIVERSITY, KOTTAYAM, KERALA, INDIA
M.Sc. BOTANY DEGREE EXAMINATION, JULY 2004
Faculty of Sciences, Branch VI – Botany
PAPER – VI – CELL BIOLOGY, GENETICS AND PLANT BREEDING
Time: Three Hours Maximum: 75 Marks
Section A (Cell Biology)
I. Answer any seven of the following: (7 X 1 = 7 Marks)
1. Explain breakage-fusion-bridge cycle.
2. Write notes on Renner complex.
3. What are the applications of colchiploidy?
4. Give an account of fragile sites on chromosome.
5. Comment on synaptonemal complex.
6. What is a sesquidiploid?
7. What is Ph-Chromosome?
8. Write notes on plastomes.
9. Describe the structure of plasmodesmata.
II. Answer any two of the following: (2 X 4 = 8 Marks)
10. Describe the different types of mobile genetic elements and their role in plants.
11. Describe the various structural variations of chromosomes. Explain their meiotic behavior.
12. Explain radio isotopes and their applications.
III. Answer any one of the following: (1 X 8 = 8 Marks)
13. Discuss the structural details of various types of supernumerary chromosomes and giant chromosomes. Mention their significance.
14. Compare the chromosome mechanisms and events in mitosis and meiosis. Describe their significance
Section B (Genetics)
IV. Answer any five of the following: (5 X 1 = 5 Marks)
15. Write notes on Okazaki fragments.
16. What is pleiotropism?
17. What are spliceosomes?
18. What are pseudo-alleles?
19. Describe chromosome walking.
20. Write notes on polygenic inheritance.
V. Answer any three of the following: (3 X 2 = 6 Marks)
21. Differentiate c-value from c-value paradox.
22. Distinguish Transposons from retroposons.
23. Comment on the terms eugenics, euphenics and euthenics.
24. What do you mean by antisense technology?
VI. Answer any three of the following: (3 X 4 = 12 Marks)
25. Write notes on polygenic inheritance. Site examples.
26. Describe the various types of DNA repair mechanisms.
27. Describe Polymerase Chain Reaction. What are its applications?
28. Give a detailed account of recombinant DNA technology.
VII. Answer any two of the following: (2 X 7 = 14 Marks)
29. “Transgenesis involves genetic transformation by non-sexual means”-Evaluate.
30. Describe the various DNA sequencing mechanisms.
31. Give a detailed account of the molecular mechanisms of transcription, translation in Prokaryotes and Eukaryotes.
Section C (Plant Breeding)
VIII. Answer any four of the following: (4 X 2 = 8 Marks)
32. Explain resistance breeding and comment on its significance.
33. Briefly describe the role of induced mutations in crop improvement.
34. Briefly discuss the applications of distant hybridization in crop improvement.
35. What is meant by bulk method of selection? What are its merits and demerits?
36. Describe briefly the genetic basis and effects of heterosis and inbreeding depression.
IX. Answer any one of the following: (1 X 7 = 7 Marks)
37. Outline the methodology and achievements of polyploidy breeding in crop improvement.
38. Discuss the centers of diversity and origin of cultivated plants.