NEET BIOLOGY

Detailed explanation-1: -In meiosis, the chromosomes duplicate (during interphase) and homologous chromosomes exchange genetic information (chromosomal crossover) during the first division, called meiosis I. The daughter cells divide again in meiosis II, splitting up sister chromatids to form haploid gametes.

Detailed explanation-2: -Summary of Meiosis I The chromosomes are copied during interphase (prior to meiosis I). This forms two identical sister chromatids that are attached together at the centromere. During prophase I, crossing over introduces genetic variation by swapping pieces of homologous chromosomes.

Detailed explanation-3: -Common mistakes and misconceptions. Interphase is not part of meiosis. Although a cell needs to undergo interphase before entering meiosis, interphase is technically not part of meiosis. Crossing over occurs only during prophase I.

Detailed explanation-4: -Interphase doesn’t occur a second time because after the first division of meiosis the cell only contains half the chromosomes necessary to perform its functions.

Detailed explanation-5: -Meiosis is preceded by an interphase which is nearly identical to the interphase preceding mitosis. During interphase, the DNA of the chromosomes is replicated (during S phase).