MAHATMA GANDHI UNIVERSITY, KOTTAYAM, KERALA, INDIA
M.Sc. BOTANY DEGREE EXAMINATION, JULY 2002
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. Write an account on Ph-chromosome.
2. Discuss the role of extrinsic and intrinsic proteins.
3. Comment on polyhaploid
4. Explain satellite DNA.
5. Write notes on Philadelphia chromosome
6. Explain chondrome.
7. Comment on plasmodesmata.
8. Explain the structure and functions of spindle apparatus.
9. Give an account on chromosome library.
II. Answer any two of the following: (2 X 4 = 8 Marks)
10. Give an account of the various theories on the origin of cell organelles.
11. Describe the role of mobile genetic elements in plants.
12. Write an account of the effects of high-energy radiation on chromosomes.
III. Answer any one of the following: (1 X 8 = 8 Marks)
13. Compare the chromosome mechanisms and events in mitosis and meiosis. Describe their significance.
14. Describe in detail the various chromosome banding techniques. How is it useful in karyotype analysis?
Section B (Genetics)
IV. Answer any five of the following: (5 X 1 = 5 Marks)
15. Comment on RFLP.
16. Write an account on Cryptic genes.
17. Explain pleiotropism.
18. What is gene erosion?
19. Give an account on IS elements.
20. Write notes on selfish genes.
V. Answer any three of the following: (3 X 2 = 6 Marks)
21. Give an account on genetic polymorphism.
22. Distinguish between modifiers and suppressors.
23. Describe the biochemical mutations observed in Neurospora.
24. Compare the repetitive and unique DNA sequences.
VI. Answer any three of the following: (3 X 4 = 12 Marks)
25. Give an account of site directed mutagenesis. What are tis applications?
26. Write notes on the polygenic inheritance, site examples.
27. Describe the principles, methods and applications of blotting techniques.
28. Categorize the different forms of DNA. How do they differ from each other?
VII. Answer any two of the following: (2 X 7 = 14 Marks)
29. Give a detailed account on DNA repair mechanism. Add a note on ageing.
30. Distinguish between the regulation of gene expression in prokaryotes and eukaryotes.
31. What is Hardy-Weinberg’s law? How is it useful in predicting gene frequencies in a population? Explain with examples.
Section C (Plant Breeding)
VIII. Answer any four of the following: (4 X 2 = 8 Marks)
32. Distinguish between dominance and over-dominance hypothesis.
33. Explain the genetic basis of male sterility in plants.
34. Describe the major achievements of selection breeding.
35. Distinguish between heterosis and heterobeltiosis.
36. Differentiate between horizontal and vertical resistance.
IX. Answer any one of the following: (1 X 7 = 7 Marks)
37. Give a detailed account of molecular techniques utilized for crop improvement
38. Briefly discuss the concept of centers of origin of species. How is this information useful in plant breeding?