Assertion : Chiasmata is formed during diplotene. Reason : Chiasmata are formed due to deposition of nucleoproteins.

 

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Assertion : Chiasmata is formed during diplotene. 
Reason  : Chiasmata are formed due to deposition of nucleoproteins.
 (a) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
 (b) If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
(c) If Assertion is true but Reason is false. 
(d) If both Assertion and Reason are false. 

Answer: (c) If Assertion is true but Reason is false. 

The beginning of diplotene is recognised by the dissolution of the

synaptonemal complex and the tendency of the recombined

homologous chromosomes of the bivalents to separate from each other

except at the sites of crossovers. These X-shaped structures, are called

chiasmata. In oocytes of some vertebrates, diplotene can last for

months or years.

The final stage of meiotic prophase I is diakinesis. This is marked by

terminalisation of chiasmata. During this phase the chromosomes are

fully condensed and the meiotic spindle is assembled to prepare the

homologous chromosomes for separation. By the end of diakinesis, the

nucleolus disappears and the nuclear envelope also breaks down.

Diakinesis represents transition to metaphase.