E2P1/19A16 Reg. No St. Joseph’s college of Arts & Science (Autonomous) St. Joseph’s College Road, Cuddalore – 607001 PBC805S-MOLECULAR BIOLOGY Time : 3 hrs

Max Marks :75

SECTION – A Answer ALL the questions I Choose the best answer: (5X1=5) 1. The lowest level of chromosome organization is a) solenoid

b) nucleosome

c) 30 nm fibre d) none of these

2.____________ is the eukaryotic origin of replication a) ARSb) ORCc) Ori Cd)Ori R 3._________ genes expression is not regulated? a) Regulator

b) Constitutive

c) Suppressor d) Repressor

4. Which of the following is not a stop codon? a) UAA

b) UGA

c) UGG

d) UAG

5. Proteins targeted to mitochondrial matrix are tagged with matrix targeting sequence rich in a) Ser and Thr

b) Ser,Thr, Lys and Arg

c) Ser,Thr, Gln and Asn

d) Ser,Thr, Trp and His

II. Say true or false (5X1=5) 6. Heterochromatin is highly condensed form of DNA 7. During DNA chain elongation, gap formed is filled by DNA ligase 8. The NusA protein acts as a termination factor 9. Leucine, Arginine and Serine have six codons each

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E2P1/19A16 10. S-adenosyl methionine act as an adenosine donor during post translational modification III. Answer in one sentence (5X1=5) 11. Define satellite DNA? 12. What are Okazaki fragments? 13. What are repressors? 14. Mention the role of peptidyl transferase 15.What is SRP? SECTION-B (5X4=20) Answer ALL the questions: 16. a) Write short notes on eukaryotic chromosome organization (Or) b) Give an account on mitochondrial DNA 17. a) Elaborate the factors involved in prokaryotic DNA replication (Or) b) Explain rolling circle replication 18. a) Describe RNA splicing for group II introns (Or) b) Write short notes on prokaryotic and eukaryotic RNA polymerases 19. a) Whatare codons? Describe the features of genetic code (Or) b) Discuss on inhibitors of protein synthesis 20. a) What is SNARE? Describe its biological role (Or) b) What are transposons? Explain their types

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E2P1/19A16 SECTION-C (4X10=40) Answer any FOUR questions: 21. Describe the experimental proves for DNA as genetic material 22. Elucidate how DNA is replicated in prokaryotes 23. Elaborate how trp operon is regulated 24. Explain the mechanism of protein synthesis in prokaryotes with neat sequence of diagram 25. Give a detailed account on base and nucleotide excision repair mechanisms 26. Explain the mechanism of protein targeting into mitochondrial matrix

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