LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034 M.Sc. DEGREE EXAMINATION - BIO TECHNOLOGY FIRST SEMESTER – November 2008 BT 1815 - CELL & MOLECULAR GENETICS Date : 08-11-08 Time : 1:00 - 4:00 Dept. No. ED 29 Max. : 100 Marks PART – A ANSWER ALL THE QUESTIONS. I. Choose the correct answer: 1. Crossing over occurs in which stage of meiosis ? (a) Leptotene (b) Zygotene (c) Pachytene (d) Diplotene (5 x 1 = 5) 2. Which is a stop codon? (a) AUG (b) UGA (c) AAA (d) GGG 3. The size of DNA is (a) 12 nm (b) 2 nm (c) 1 nm (d) 10 nm 4. Which organism has the least number of chromosomes? (a) Drosophila (b) Arabidopsis (c) Chironomous (d) Ascaris 5. Recombination distance is measured in which units? (a) Morgan (b) centi-Morgan (c) Kilo basepairs (d) Mega basepairs II. State whether the following are True or False, if false give reason 6. The resolving power of human eye is 0.01mm 7. Histone genes contain poly A tails. 8. Paracentric inversion does not include centromere 9. NO is an example of second messenger. 10. Hardey – Weinberg law is used to study Population Genetics (5 x 1 = 5) III. Complete the following: (5 x 1=5) 11. The power house of the cell is ________________. 12. Sense strand is also called as_________ strand or _________ strand 13. Barbara McClintok discovered _____________ 14. Down’s syndrome is an example of ___________and in Humans it is due to _________ 15. LOD score stands for _____________ IV. Answer the following within 50 words only: 16. 17. 18. 19. 20. 1 Define the term evolution Define the term Genome What is Shine- Dalgarno sequence? What are transposal elements? What is Quantitative inheritance ? (5 x 1=5) PART B V. Answer any five questions, each within 350 words only, draw diagram where required (5 x 8 = 40) 21. Give an account on Microtubules. 22. Enumerate the sequential steps involved in the replication of prokaryotic DNA? 23. Explain the chromatin organization schematically. 24. Write an account on polytene chromosome. 25. Enumerate the differences between positive and negative gene regulation in prokaryote 26. What is a mutation. What are the various types and give examples of each kind. 27. What is Hardy – Weinberg Law of Equilibrium? Give a short account of it. 28. Enumerate the differences between Quantitative and Qualitative inheritances, cite two examples each. PART C VI. Answer the following in detail, each within 1500 words only, draw diagram where required (2 x 20 = 40) 29. (a) What is cell cycle? Give a detailed account of the various phases involved in cell cycle. Add a note on the importance of cell cycle control molecules. OR (b) Explain in detail contact dependent, paracrine, synaptic and endocrine forms of intracellular signaling with appropriate diagrams and examples 30. (a) Describe various laws of heredity using appropriate examples, one of each category. OR (b) Discuss in detail different types of extrachromosomal inheritances seen, using specific examples of each kind ************** 2