Q8/19A/10-14 Reg. No

St. Joseph’s College of Arts & Science (Autonomous) St. Joseph’s College Road, Cuddalore – 607001 PBC805 – MOLECULAR BIOLOGY

Time : 3 hrs

Max Marks :75 SECTION – A (25X1=25) Answer ALL Questions

I. Choose the correct answer 1. The enzyme responsible for initiating DNA replication in prokaryotes is a. DNA Polymerase I b. DNA Polymerase III c. Polymerase beta d. Primase 2. Which out of the following is an inhibitor of prokaryotic transcription? a. Ciprofloxacin b. Etoposide c. Erythromycin d. Rifampicin 3. Restriction endonucleases are enzymes – a. Used for joining DNA to cloning vector b. That cleave randomly c. That digest DNA from ends d. Cleave DNA at specific sites 4. Promoters for tRNAs are located a. Upstream from the start codon b. Downstream from the start codon c. Both (a) and (b) d. None of these 5. Transcription factors are a. Promoters b. Proteins which bind to DNA and regulate transcription c. TATA boxes d. CATT boxes

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Q8/19A/10-14 6. The accepted hypothesis for DNA replication is a. Conservative theory b. Dispersive theory c. Semi-conservative theory d. Evolutionary theory 7. Messelsen and Stahl model of replication was called a. Conservative replication b. Semi-conservative replication c. Dispersive replication d. Cri du Chat 8. The haploid set of the chromosomes is called as a. Proteome b. Genomics c. Genome

d. Genes

9. A functional chromosome has a. A centromere c. An origin of replication

b. A telomere d. All of these

10. Dimer repair mechanism include a. Excision repair c. Recombinational repair

b. Photoreactivation d. All of these

II. State true or false 11. The mutation which will not affect the length of a protein is missense mutation. 12. The enzyme that catalyses the synthesis of DNA is called DNA polymerase. 13. AUAUA is the usual sequence of a pribnow box. 14. DNA polymerase is necessary for transcription to occur. 15. Ligase is not necessary componenet of translation. III. Answer in a sentence on two sentences 16. What is Satellite DNA? 17. Define cot Value. 18. What are Type II topoisomerases? 19. What are Physical mutagens?

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Q8/19A/10-14 20. Name the inhibitors of transcription. 21. Define Wobble hypothesis. 22. What are the characteristics of genetic code? 23. Define Primer. 24. Define exons. 25. Define gene. SECTION – B (5X4=20) Answer any FOUR Questions 26. Explain Griffith experiment. 27. Write a detailed note on organization of genes. 28. Write notes on RNA polymerases. 29. Explain the post translational modifications of proteins. 30. Write a note on gene amplification. 31. Describe the positive and negative regulation of lac operon. SECTION – C (3X10=30) Answer any THREE Questions 32. Discuss the experiments of Griffith, Mcloed, Mccarty and Averty. 33. Explain the steps involved in RNA synthesis. 34. Write an essay on chromosomal aberrations. 35. Discuss Operon concept. 36. Elaborate on protein synthesis.

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