Understand the Meiosis Process: Reduction in DNA Content and Ploidy Level Explained

PART C – Changes in ploidy and DNA content during meiosisThe parent cell that enters meiosis is diploid, whereas the four daughter cells that result are haploid.Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II?

DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II.[During anaphase of both meiosis I and meiosis II, the DNA content (number of copies of chromosomes) in a cell is halved. However, the ploidy level changes only when the number of unique chromosome sets in the cell changes. This occurs only in meiosis I (where separation of homologous chromosomes decreases the ploidy level from 2n to n and produces daughter cells with a single chromosome set).]

During meiosis I, the parent cell with diploid DNA content undergoes recombination and synapses, followed by homologous chromosome separation, resulting in two cells that are haploid in their DNA content but still diploid in ploidy level. During meiosis II, the sister chromatids are separated into individual daughter cells, reducing the ploidy level to haploid and maintaining the haploid DNA content of each cell. Thus, by the end of meiosis II, four haploid daughter cells are generated from one diploid parent cell, each containing half the amount of DNA as the original parent cell. Therefore, the cellular DNA content and ploidy levels change during meiosis to reduce the DNA content by half and the ploidy level from diploid to haploid.

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