Q. No.During DNA replication the leading and lagging strands are synthesized differently. The reason for this difference is:
1.
DNA polymerase can work only on one strand at a time
2.
The single-strand binding proteins cannot bind to both strands of DNA
3.
DNA ligase works only in the 3ʹ →5ʹ direction
4.
DNA polymerase can add new nucleotides only to the 3’ end of a growing strand
Identify the incorrect match between the scientists in Column I with their contributions in Column II:
|
|
COLUMN I |
COLUMN II |
|
1. |
Frederick Griffith |
Discovery of bacterial transformation |
|
2. |
Meselson and Stahl |
Proposed semi-conservative mode of DNA replication based on complementary base pairing and antiparallel strands |
|
3. |
Avery, Macleod, and McCarty |
Purified the transforming principle and found it to be DNA |
|
4. |
Erwin Chargaff |
In natural DNA the number of guanine units equals the number of cytosine units and the number of adenine units equals the number of thymine units |
The lac I gene in an E. coli bacterium is mutated. What will be the effect on the regulation of lactose metabolism in this cell?
| 1. | Regulation will be normal. |
| 2. | There will be a constitutive expression of the lac Z gene. |
| 3. | Beta-galactosidase and lactose permease will not be produced in the cell. |
| 4. | The lac repressor will be synthesized continuously at a slow rate. |
Which of the following is not a correct finding of the human genome project [based on the information given in the NCERT textbook]?
|
1. |
Number of base pairs |
3164.7 million |
|
2. |
Percent of the genome that codes for proteins |
Less than 2 |
|
3. |
Total number of genes |
About 30000 |
|
4. |
Locations at which ‘snips’ present |
2.1 million |
DNA-dependent DNA polymerases do not:
| 1. | synthesize RNA to prime DNA synthesis |
| 2. | have exonuclease activity |
| 3. | possess proofreading capabilities |
| 4. | synthesize DNA in a 5' to 3' direction |
In a transcription unit, what defines the template and coding strands?
| 1. | The promoter | 2. | The structural gene |
| 3. | The terminator | 4. | The regulators |
In molecular biology, ‘rho [ρ] is a:
| 1. | 5' capping factor |
| 2. | polyadenylation factor |
| 3. | termination factor for transcription |
| 4. | An initiation factor for transcription |
The correct chronological order of the steps of translation of a prokaryotic mRNA will be:
| I: | attachment of the initiator tRNA onto the start codon |
| II: | binding of the mRNA to small ribosome subunit of a ribosome |
| III: | attachment of the large ribosome subunit to the mRNA |
| IV: | translocation of the ribosome to move a new codon to be in the A site |
| V: | entry of a charged tRNA into the A site |
| 1. | I | II | V | III | IV |
| 2. | II | I | III | V | IV |
| 3. | I | II | III | V | IV |
| 4. | II | I | IV | III | V |
Consider the given two statements:
| I: | Among the two nucleic acids DNA is a better genetic material. |
| II: | The protein synthesizing machinery has evolved around RNA and not DNA. |
| 1. | Both I and II are correct and II explains I |
| 2. | Both I and II are correct but II does not explain I |
| 3. | I is correct but II is incorrect |
| 4. | Both I and II are incorrect |
What would be true for both Eukaryotic and Prokaryotic gene expression?
| 1. | Coupling of transcription and translation |
| 2. | Post-transcriptional removal of introns |
| 3. | Binding of RNA polymerase to the promoter to initiate transcription |
| 4. | The eukaryotic hnRNA and prokaryotic RNA are polycistronic |
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