Molecular Biology

Set No. 1

Code No: R05222303

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2007 MOLECULAR BIOLOGY (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. What does “right handed helix” & “left handed helix” mean? Explain taking suitable examples. [16] 2. How does rolling circle replication produce multimers of a replicon?

[16]

3. How is the lagging strand synthesis different from the leading strand synthesis in DNA replication? [16] 4. Justify the statement “there are different types of rRNA found in ribosome” [16] 5. Using suitable examples explain how they are acting as inhibitors of transcription. [16] 6. What is meant by “Wobble hypothesis”? Explain its connection to the genetic code. [16] 7. How is the initiation of translation process occurring in prokaryotes and eukaryotes? Elaborate briefly. [16] 8. Write short notes on

[2 × 8 = 16]

(a) Thiamine dimmers and photo reactivation (b) Excision type of DNA repair ⋆⋆⋆⋆⋆

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Set No. 2

Code No: R05222303

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2007 MOLECULAR BIOLOGY (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. What does “right handed helix” & “left handed helix” mean? Explain taking suitable examples. [16] 2. Using neat diagrams explain a circular chromosome undergoing bi-directional semi conservative replication. [16] 3. Explain the process of DNA replication in detail.

[16]

4. Discuss in detail the structure of the organelles functioning as sites of protein synthesis. [16] 5. Using suitable examples explain how they are acting as inhibitors of transcription. [16] 6. In the genetic code, how can one justify the presence of 64 codons coding for only 20 amino acids. [16] 7. Once a protein is synthesized, can it be modified? Justify your answer giving suitable examples. [16] 8. With the help of a neat diagram explain how the process of site directed mutagenesis is done. [16] ⋆⋆⋆⋆⋆

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Set No. 3

Code No: R05222303

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2007 MOLECULAR BIOLOGY (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Write a note on the different forms of the double helix DNA and elaborate on “B” form. [16] 2. How does the bacteriophage Φ×174 replicate through rolling circle mechanism? [16] 3. What is meant by ‘end replication problem’ in DNA synthesis? Discuss the role of telomase in it. [16] 4. Write about the different types of ribonucleic acids.

[16]

5. Where does the synthesis & processing of pre-rRNA occur? Explain the process. [16] 6. Write briefly about the steps of initiation, elongation and termination in the process of prokaryotic translation. [16] 7. What are post transnational modifications? Give some examples.

[16]

8. How is reverse genetics approach used to study a gene function?

[16]

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Set No. 4

Code No: R05222303

II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2007 MOLECULAR BIOLOGY (Bio-Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Explain how GC base pair content of a ds DNA affects the melting temperature Tm. [16] 2. With respect to DNA replication, explain (a) Origin of replication (b) Replication fork (c) Bidirectional replication (d) Semi-conservative replication.

[4 × 4 = 16]

3. How does DNA replication proceed in the 5’ − > 3’ polarity parental DNA strand? [16] 4. Give a step-by-step description of the process of Transcription.

[16]

5. Describe briefly about the posttranscriptional processing occurring in eukaryotic mRNA. [16] 6. In the genetic code, how can one justify the presence of 64 codons coding for only 20 amino acids. [16] 7. With context to gene transfer mechanisms, explain

[2 × 8 = 16]

(a) Transduction (b) Conjugation 8. Explain how base analogs and alkylating agents act as chemical mutagens in induced mutations. [16] ⋆⋆⋆⋆⋆

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