Consider the given two statements:
I: | The type of regulation that the lac operon undergoes is referred to as negative inducible. |
II: | The operon is turned off by the regulatory factor (lac repressor) unless some molecule (lactose) is added. |
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. Only I is correct.
4. Both I and II are incorrect
Only two people have twice won the Nobel Prize in the same category. One was John Bardeen in Physics and the other in Chemistry. Identify this other person whose contributions are listed below:
(i) for his work on the structure of proteins, especially that of insulin
(ii) for contributions concerning the determination of base sequences in nucleic acids [genome sequencing]
1. | Linus Pauling | 2. | Marie Curie |
3. | Paul Berg | 4. | Frederick Sanger |
The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The properties of RNA make the idea of the RNA world hypothesis conceptually plausible and include:
I. RNA is known to form efficient catalysts
II. Its similarity to DNA makes clear its ability to store information
1. | Only I | 2. | Only II |
3. | Both I and II | 4. | Neither I nor II |
Consider the given statements regarding replication of DNA:
I. DNA is read by DNA polymerase in the 5′ to 3′ direction, meaning the new strand is synthesized in the 3' to 5' direction.
II. The leading strand is the strand of new DNA that is synthesized in the same direction as the growing replication fork.
III. The lagging strand is the strand of new DNA whose direction of synthesis is opposite to the direction of the growing replication fork.
1. Only I and II are correct
2. Only I and III are correct
3. Only II and III are correct
4. I, II and III are correct
As opposed to DNA replication, transcription:
I. results in an RNA complement that includes the nucleotide uracil (U) in all instances where thymine (T) would have occurred in a DNA complement.
II. creates complementary RNA in 3’ – 5’ direction
1. Only I is correct
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
In Meselson and Stahl experiment, DNA extracted from the culture, one generation after the transfer from 15N to 14N medium, had a hybrid or intermediate density. With each subsequent round of replication, the percentage of hybrid or intermediate-density DNA molecules extracted from the culture:
1. will remain same
2. will get reduced by half
3. will get increased by half
4. will get doubled
I: | The lack of 35S-labeled DNA remaining in the solution after the bacteriophages had been allowed to adsorb to the bacteria showed that the phage DNA was transferred into the bacterial cell. |
II: | The presence of almost all the radioactive 32P in the solution showed that the protein coat that protects the DNA before adsorption stayed outside the cell. |
1. | Only I | 2. | Only II |
3. | Both I and II | 4. | Neither I nor II |