1. | is much lengthy in duration. |
2. | leads to reduction in the number of chromosomes. |
3. | is characterised by replication of DNA just before its beginning. |
4. | resembles a normal mitosis. |
I: | organism to organism |
II: | from cell type to cell type in the same organism |
I: | the amount of DNA per cell doubles |
II: | there is no increase in the chromosome number |
Assertion (A): | Meiosis is the mechanism by which conservation of specific chromosome number of each species is achieved across generations in sexually reproducing organisms. |
Reason (R): | Cells in G0 stage no longer remain metabolically active and no longer proliferate unless called on to do so depending on the requirement of the organism. |
1. | (A) is True; (R) is False |
2. | Both (A) and (R) are True and (R) correctly explains (A) |
3. | Both (A) and (R) are True but (R) does not correctly explain (A) |
4. | (A) is False; (R) is True |
Statement I: | With few exceptions, in animals, mitotic cell division is generally only seen in the diploid somatic cells. |
Statement II: | The plants can show mitotic divisions in both haploid and diploid cells. |
Statement I: | At the time of cytoplasmic division, organelles like mitochondria and plastids get distributed between the two daughter cells. |
Statement II: | In some organisms karyokinesis is not followed by cytokinesis as a result of which multinucleate condition arises leading to the formation of syncytium (e.g., liquid endosperm in coconut). |
I: | Mitosis usually results in the production of diploid daughter cells with identical genetic complement. |
II: | The growth of multicellular organisms is due to mitosis. |
III: | It restores the nucleo-cytoplasmic ratio of a cell. |
IV: | A very significant contribution of mitosis is cell repair. |
V: | It replaces lost cells. |
VI: | Mitotic divisions in the meristematic tissues – the apical and the lateral cambium, result in a continuous growth of plants throughout their life. |
VII: | It creates genetic variation for acting as raw material for natural selection. |
1. | 4 | 2. | 5 |
3. | 6 | 4. | 7 |
1. | interkinesis and there is no replication of DNA during this stage. |
2. | interkinesis and there is replication of DNA during this stage. |
3. | interphase II and there is no replication of DNA during this stage. |
4. | interphase II and there is replication of DNA during this stage. |