MAHATMA GANDHI UNIVERSITY, KOTTAYAM, KERALA, INDIA
M.Sc. BOTANY DEGREE EXAMINATION, JUNE 2012
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. What are isotopes?
2. Role of colchicine in the induction of polyploidy.
3. What is chromosome banding?
4. Give the structure of spindle apparatus.
5. Fragile sites in chromosomes.
8. Renner complex
9. Importance of mitochondrial DNA in cells.
II. Answer any two of the following: (2 X 4 = 8 Marks)
10. Write a short note on molecular organization of chromosomes.
11. Give a short account of giant chromosomes.
12. Briefly describe karyotype analysis.
III. Answer any one of the following: (1 X 8 = 8 Marks)
13. Write an essay on the similarities and differences between mitosis and meiosis.
14. What are the biological, physiological and chromosomal effects of radiations?
Section B (Genetics)
IV. Answer any five of the following: (5 X 1 = 5 Marks)
15. DNA fingerprinting
16. Restriction endonucleases
17. DNA methylation
18. Protein targeting
19. IS elements
20. C-value paradox
V. Answer any three of the following: (3 X 2 = 6 Marks)
21. Penetrance and expressivity of genes.
22. Haploid mapping in Neurospora.
23. Oncogenes and tumor suppressor genes.
VI. Answer any three of the following: (3 X 4 = 12 Marks)
25. Features of genetic code.
26. Describe biochemical mutations in Neurospora
27. Semiconservative replication of DNA and Measelson-Stahl experiment.
28. Write an account of different forms of DNA
VII. Answer any two of the following: (2 X 7 = 14 Marks)
29. What is hardy-Weinberg law? Describe its applications in genetics.
30. What do you mean by DNA repair mechanism? Give an account of various types seen in cells.
31. Write an essay on the regulation of gene expression in prokaryotes.
Section C (Plant Breeding)
VIII. Answer any four of the following: (4 X 2 = 8 Marks)
32. Genetic variability and its role in plant breeding.
33. Why back cross method is used in hybridization techniques?
34. Describe the genetic basis of heterosis.
35. What are the different mechanisms of disease resistance?
36. Limitations of somatic hybridization in plant breeding.
IX. Answer any one of the following: (1 X 7 = 7 Marks)
37. Discuss the role of mutation in plant breeding.
38. Explain the methods of breeding for disease resistance.