| Assertion (A): | Retroviruses are one known exception to the central dogma in molecular biology as proposed by Francis Crick. |
| Reason (R): | In retroviruses a sequence of nucleotides is copied from an RNA template during the synthesis of a molecule of DNA. |
| 1. | Both (A) and (R) are True but (R) does not correctly explain (A). |
| 2. | (A) is True but (R) is False. |
| 3. | (A) is False but (R) is True. |
| 4. | Both (A) and (R) are True and (R) correctly explains (A). |
| I: | is formed by the wrapping of negatively charged DNA around the negatively charged histone octamer. |
| II: | typically contains 200 bp of DNA helix. |
| III: | constitutes the repeating unit of a structure in nucleus called chromatin. |
| IV: | is seen as ‘beads-on-string’ structure when viewed under electron microscope (EM). |
| Assertion (A): | Euchromatin is said to be transcriptionally active chromatin, whereas heterochromatin is inactive. |
| Reason (R): | Light stained region of chromatin is euchromatin and dark stained region is heterochromatin. |
| 1. | Both (A) and (R) are True but (R) does not correctly explain (A). |
| 2. | (A) is True but (R) is False. |
| 3. | (A) is False but (R) is True. |
| 4. | Both (A) and (R) are True and (R) correctly explains (A). |
| 1. | The R strain bacteria had somehow been transformed by the heat-killed S strain bacteria. |
| 2. | Some ‘transforming principle’, transferred from the heat-killed S strain, had enabled the R strain to synthesise a smooth polysaccharide coat and become virulent. |
| 3. | The transformation must be due to the transfer of the genetic material. |
| 4. | The biochemical nature of genetic material must be the protein |
| Statement I: | Bacteria that were infected with viruses that had radioactive proteins were not radioactive. |
| Statement II: | Proteins did not enter the bacteria from the viruses. |
| 1. | Statement I is correct; Statement II is incorrect |
| 2. | Statement I is incorrect; Statement II is incorrect |
| 3. | Statement I is correct; Statement II is correct |
| 4. | Statement I is incorrect; Statement II is correct |
| I: | Both the nucleic acids (DNA and RNA) can act as the genetic material. |
| II: | Proteins cannot act as the genetic material. |
| 1. | Only I is correct |
| 2. | Only II is correct |
| 3. | Both I and II are correct |
| 4. | Both I and II are incorrect |
| Assertion (A): | Viruses having RNA genome and having shorter life span mutate and evolve faster. |
| Reason (R): | RNA being unstable, mutates at a faster rate. |
| 1. | Both (A) and (R) are True but (R) does not correctly explain (A). |
| 2. | (A) is True but (R) is False. |
| 3. | (A) is False but (R) is True. |
| 4. | Both (A) and (R) are True and (R) correctly explains (A). |
| 1. | two old strands |
| 2. | two new strands |
| 3. | one old and one new strand |
| 4. | two strands with variable proportion of new and old DNA |
| Assertion (A): | On one strand (the template with polarity 3'→5'), the replication is continuous, while on the other (the template with polarity 5'→3'), it is discontinuous. |
| Reason (R): | The DNA-dependent DNA polymerases catalyse polymerisation only in one direction, that is 3'→5'. |
| 1. | Both (A) and (R) are True but (R) does not correctly explain (A). |
| 2. | (A) is True but (R) is False. |
| 3. | (A) is False but (R) is True. |
| 4. | Both (A) and (R) are True and (R) correctly explains (A). |
| 1. | has the polarity 3'→5' |
| 2. | has the sequence same as RNA (except uracil at the place of thymine) |
| 3. | is displaced during transcription |
| 4. | codes for the transcript formed |