Which of the following does not take place during telophase of mitosis?
1. | Chromosomes become discrete. |
2. | Nuclear envelope reforms. |
3. | Chromosomes cluster at opposite spindle poles. |
4. | Nucleolus, endoplasmic reticulum, and Golgi complex reform. |
1. | Chromosomes line up at the equatorial plate in anaphase I of meiosis |
2. | Sister chromatids separate in mitosis anaphase, whereas homologous chromosomes separate in anaphase I of meiosis |
3. | Only mitosis anaphase leads to genetically identical daughter cells |
4. | Anaphase I of meiosis does not involve spindle fibers |
I: | At metaphase I, the microtubules from the opposite poles of the spindle attach to the pair of homologous chromosomes. |
II: | At anaphase I, the homologous chromosomes separate, while sister chromatids remain associated with each other. |
I: | Gametes contain half the number of chromosomes found in somatic cells. |
II: | Somatic cells have the diploid number of chromosomes. |
III: | The haploid number of chromosomes in humans is 23. |
IV: | The diploid number of chromosomes in humans is 23 pairs. |
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): | Meiosis results in reduction of chromosome number by half in gametes. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
1. | Zygotene | 2. | Pachytene |
3. | Diplotene | 4. | Diakinesis |
I: | In an animal cell, cytokinesis is achieved by the appearance of a furrow in the plasma membrane. |
II: | In plant cells, wall formation starts in the centre of the cell and grows outward to meet the existing lateral walls. |
III: | At the time of cytoplasmic division, organelles like mitochondria and plastids get distributed between the two daughter cells. |
1. | 0 | 2. | 1 |
3. | 2 | 4. | 3 |
Statement I: | Centromeres split and chromatids separate. |
Statement II: | Chromatids move to opposite poles. |
1. | Statement I is correct and Statement II is incorrect. |
2. | Statement I is incorrect and Statement II is incorrect. |
3. | Statement I is correct and Statement II is correct. |
4. | Statement I is incorrect and Statement II is correct. |
I: | are small disc-shaped structures at the surface of the centromeres. |
II: | serve as the sites of attachment of spindle fibres to the chromosomes. |
III: | are same as centromeres. |
Assertion (A): | Metaphase is the stage at which morphology of chromosomes is most easily studied. |
Reason (R) : | At metaphase, condensation of chromosomes is completed. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |