Assertion (A): | Meiosis does not occur in haploids cells. |
Reason (R): | Haploid cells do not form 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. | Both (A) and (R) are false. |
Metaphase I is different from mitotic metaphase as in the later case
1. | Two metaphasic plates are formed |
2. | Tetrads are arranged at the equator |
3. | Single metaphasic plate is formed |
4. | Homologous chromosomes get separated from each other |
Assertion (A): | During anaphase-1 of meiosis, non-homologous chromosomes separate. |
Reason (R): | There is splitting of centromere during anaphase-1. |
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. | Both (A) and (R) are false. |
(i) | It begins with the dissolution of the synaptonemal complex. |
(ii) | Homologous chromosomes tend to separate except at the sites of crossing over. |
(iii) | The recombination nodules become more prominent during diplotene. |
Select the correct sequence of events occurring during prophase-I of meiosis-I
(a) | Nuclear envelope breakdown |
(b) | Synaptonemal complex formation |
(c) | Compaction of chromosomes |
(d) | Terminalisation of chiasmata |
(e) | Crossing over |
Choose the most appropriate answer from the options given below:
1. | (c) → (b) → (e) → (d) → (a) |
2. | (c) → (a) → (b) → (d) → (e) |
3. | (b) → (c) → (a) → (d) → (e) |
4. | (c) → (a) → (b) → (e) → (d) |
1. | 24 | 2. | 6 |
3. | 12 | 4. | 18 |
Statement I: | The nuclear membrane and nucleolus reappear. |
Statement II: | The chromosomes reach the extremely extended state of the interphase nucleus. |
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. |
Statement I: | At Metaphase I the chromosomes align at the equator and the microtubules from opposite poles of the spindle get attached to the kinetochores of sister chromatids. |
Statement II: | At metaphase II the bivalent chromosomes align on the equatorial plate and microtubules from the opposite poles of the spindle attach to the kinetochore of homologous chromosomes. |
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: | terminalisation of chiasmata |
II: | decondensation of chromosomes |
III: | assembly of the meiotic spindle |