NEETBotanyCell Cycle and Cell Division
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In some vertebrate oocytes, the diplotene stage can last for months or years. Reason (R): During diplotene, the synaptonemal complex dissolves and the recombined homologous chromosomes separate from each other except at the sites of crossovers. In the light of the above statements, choose the most
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- B(A) is correct but (R) is not correct
- CBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- D(A) is not correct but (R) is correct
Correct answer
C. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
Step-by-step solution
Assertion (A) is a correct statement as per NCERT; in the oocytes of some vertebrates, the diplotene stage is arrested and can last for months or years to allow for the accumulation of resources. Reason (R) is also a correct statement. The beginning of the diplotene stage is indeed recognised by the dissolution of the synaptonemal complex and the separation of recombined homologous chromosomes except at the chiasmata. However, the cytological events of diplotene described in the Reason do not explain why the stage