- 1(current)
Q. No.DNA replication is semi-conservative in nature was experimentally proved in eukaryotes by:
1. Hershey and Chase
2. Macleod and McCarty
3. Meselson and Stahl
4. Talyor and his colleagues
Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R)
| Assertion (A): | Semiconservative replication was experimentally proved by Mathew Meselson and Franklin Stahl (1958) |
| Reason (R): | Meselson and Stahl used radioactive isotope \(^{15}N\) and equilibrium density gradient centrifugation technique. |
In the light of the above statements, choose the correct answer from the options given below:
| 1. | (A) is correct but (R) is not correct. |
| 2. | (A) is not correct but (R) is correct. |
| 3. | Both (A) and (R) are correct and (R) is the correct explanation of (A). |
| 4. | Both (A) and (R) are correct but (R) is not the correct explanation of (A). |
What would be the proportions of light and hybrid density DNA molecule, respectively if Meselson and Stahl's experiment was continued for 60 minutes?
1. 50%, 50%
2. 25%, 75%
3. 75%, 25%
4. 100%, 0%
| Statement I: | DNA polymerases catalyse polymerisation only in one direction, that is 5' →3' |
| Statement II: | During replication of DNA, on one strand the replication is continuous while on other strand it is discontinuous. |
1. Both Statement I and Statement II are correct.
2. Both Statement I and Statement II are incorrect.
3. Statement I is correct but Statement II is incorrect.
4. Statement I is incorrect but Statement II is correct.
Choose the correct pair from the following :
| 1. | Polymerases | - | Break the DNA into fragments |
| 2. | Nucleases | - | Separate the two strands of DNA |
| 3. | Exonucleases | - | Make cuts at specific positions within DNA |
| 4. | Ligases | - | Join the two DNA molecules |
The experimental proof for semiconservative replication of DNA was first shown in a:
1. Fungus
2. Bacterium
3. Plant
4. Virus
During DNA replication, Okazaki fragments are used to elongate:
| 1. | The lagging strand towards the replication fork. |
| 2. | The leading strand away from the replication fork. |
| 3. | The lagging strand away from the replication fork. |
| 4. | The leading strand towards the replication fork. |
DNA replication in bacteria occurs:
1. Within nucleolus
2. Prior to fission
3. Just before transcription
4. During S phase
Taylor conducted the experiments to prove semi-conservative mode of chromosome replication on:
1. Vinca rosea
2. Vicia faba
3. Drosophila melanogaster
4. E. Coli
- 1(current)
Q. No.
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