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Question

Biology Question on cell cycle and cell division

Crossing over leads to recombination of genetic material on the two chromosomes. : Crossing over is the exchange of genetic material between two homologous chromosomes.

A

If both assertion and reason are true and reason is the correct explanation of assertion

B

If both assertion and reason are true but reason is not the correct explanation of assertion

C

If assertion is true but reason is false

D

If both assertion and reason are false

Answer

If both assertion and reason are true and reason is the correct explanation of assertion

Explanation

Solution

Crossing over or recombination occurs during pachytene. Recombination involves mutual exchange of the corresponding segments of non-sister chromatids of homologous chromosomes. It takes place by breakage and reunion of chromatid segments. Breakage, called nicking, is assisted by an enzyme endonuclease and reunion, termed annealing, is aided by an enzyme ligase. Crossing over leads to recombination of genetic material on the two chromosomes.