Quiz on Molecular Biology || DNA Replication and Transcription

1. Which of the following statement about fructose is true ?
Most predominant conformation of fructose in solution is β fructopyranose
In polysaccharides, fructose is seen in their furanose form
Fructose is hygroscopic
All of the above

2.The linking number of DNA
Is a topological property
Determines the degree of supercoiling
Is the sum of Twist (Tw) and Writhe (Wr)
All the above

3. The Klenow fragment of DNA polymerase I has
5'–3'exonuclease activity
3 to 5 exonuclease activity
Very high processivity
Helicase activity

4. The role of σ 70 (sigma-70) in prokaryotic transcription is
Binding DNA template
Binding regulatory sequences
Forming phosphodiester bonds
Recognizing the promoter and initiating RNA synthesis

5. Which of the following statement is incorrect regarding splicing ?
Splicing is accomplished by two transesterification reactions
At the end of splicing, the intron is released in the form of a lariant
The 2 OH of the adenine at the branch site attacks the 3 splice site
snRNAs in spliceosome catalyze the splicing of mRNA precursors

6. Lac repressor protein in the absence of inducer binds to the operator and thereby
Activates transcription
Blocks transcription
Attenuates transcription
None of the above

7. The phenomenon by which some t-RNA molecules recognize more than one codon is because of
Watson-Crick base pairing
Wobble base pairing
Hoogsteen base pairing
Purine-purine base pairing

8. Shine-Dalgarno sequence is
Centered about 10 nucleotides on the 5'side of the initiator codon
A part of prokaryotic m-RNA
A purine rich region
All the above

9. The plasmids which can be used for introducing new genes into plant cells are
R plasmids
Col plasmids
Ti plasmids
F plasmids

10. The enzyme which can be used to synthesize DNA from mRNA by providing an oligo(dT) primer that pairs with the poly (A) sequence at the 3'end of eukaryotic mRNA is
Reverse transcriptase
Restriction endonuclease
Topoisomerase
Primase

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