Biju Patnaik University of Technology 2008 B.Tech Molecular biology - Question Paper
4th Semester exam – 2008
MOLECULAR BIOLOGY Fourth Semester Examination - 2008 MOLECULAR BIOLOGY Full Marks-70
Time: 3 Hours
Answer Question No. 1 which is compulsory and any five from the rest.
The figures in the right-hand margin indicate marks.
1. Answer the following questions : 2*10
(a) What is Shine Dalgarno Sequence ? Mention the function of this sequence during translation.
(b) What is the function of Alkaline Phophatase and Taq DNA polymerase in molecular biology ?
(c) Genetic code is degenerate - Explain with suitable examples.
(d) An Hind-Ill enzyme has cleaved a genomic DNA of 4.32 *103 bp by incubating at 37 C for 2 hours. The GC content of the genome is 50%. Calculate the frequency of restriction cleavage and number of restriction fragments generated at the end of this experiment assuming it a complete digestion.
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dj gi rrm#c |
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tied we Kand,
(e) Differentiate between r/?o-dependent and r/70-independent termination of transcription.
(f) How many number of targeted DNA fragment will be generated by using PCR amplification of 30 cycles, where the initial copy number of template DNA is 6 x io6and mean efficiency of PCR is 90% ?
(g) Why DNA is known as the genetic material ? Name two evidences deliberated to show DNA is the genetic material.
(h) An oligo-nucleotide probe of 50 bp length and 54% GC content was synthesized using a DNA synthesizer. The post synthesis optical density measurement of probe was 1.082 at 260 nm. Calculate the oligonucleotide concentration of the probe.
(i) Transcription and translations are coupled in prokaryotes, but not in eukaryotes -explain the reason thereof.
(j) Define Tm of DNA. Calculate the Tm of a 15-mer primer containing 40% GC content.
2. (a) What do you mean by c-DNA and how
it differs from genomic DNA ? Briefly explain the various approaches used to generate c-DNA molecule during construction of C-DNA library. 2+5
(b) How many number of c-DNA clone is required for 99% coverage of the genome, if the cloning vector is BAC and genome size is 6 x 106 mbp. 3
3. What is Transcription ? Briefly explain the process of transcription in eukaryotes and add a note on transcription factor ll-D (TFII-D).
1+6+3
4. (a) Briefly explain the Sangers method of
DNA sequencing. How this method was automated for the sequencing of sub-genomic YAC clones ? 4+2
(b) The following is a part outcome autoradiogram of Maxam and Gilberts sequencing experiment. During the experiment the radioisotope labelled with 5 end. What is the sequence including polarity of the SS-DNA that served as template for generating this pattern. 4
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G>A A>G C+T C |
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5. (a) Briefly explain the methods of nucleic acid hybridization. Add a note on the stringency of hybridization. 5
(b) Define genome complexity. Narrate the genome composition of human with note on repetitive DNA. 5
6. (a) Briefly explain the properties and mode of action of Restriction-modification system-11 and justify the importance of Restriction endonuclease-ll enzyme in recombinant DNA experiments. 4
(b) A circular plasmid DNA molecule of size 10.5 Kbp is digested with restriction endonucleases -Eco R-l, Hind-Ill and BamH-l, singly and in all possible combinations. Linear restriction fragments of following sizes are generated :
Enzymes Fragment size in kbp
Eco R-l 10.5
Hind-Ill 5.1, 3.4, 2.0
BamH-l 7.3, 3.2
Eco R-l + Hind-Ill 4.0, 3.4, 2.0, 1.1
Eco R-l + BamH-l 6.7, 3.2, 0.6
Hind-Ill + BamH-l 4.6, 2.7, 2.0, 0.7,0.5 Eco R-l + Hind-Ill + BamH-l 4.0, 2.7, 2.0, 0.7, 0.6, 0.5.
Sketch a restriction map of the plasmid using the above data. 6
7. (a) How does RNA editing contribute to pro
tein diversity in eukaryotes ? What roles do guide RNA play in RNA editing ? 5
(b) What is Attenuation ? What role it plays in gene regulation of tryptophan operon in E. coli along with repression ? 5
8. Write down short notes on any two of the following: 5x2
(a) Cosmid as cloning vector.
(b) Enzymes involved in eukaryotic DNA replication.
(c) Post transcriptional gene silencing.
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| Earning: Approval pending. |
