Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II? (Note: Ignore any effects of crossing over.)

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Buffalo

Biology

21 December, 05:04

Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II? (Note: Ignore any effects of crossing over.)

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Bria Sweeney · Answer 1

Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II? (Note: Ignore any effects of crossing over.

a. DNA content is halved in both meiosis I and meiosis I. Ploidy level changes from diploid to haploid only in meiosis II.

b. DNA content is halved only in meiosis I. Ploidy level changes from diploid to haploid only in meiosis II.

c. DNA content is halved in both meiosis I and meiosis Il. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis lI

d. DNA content is halved only in meiosis I. Ploidy level changes from diploid to haploid in meiosis!, and remains haploid in meiosisI.

e. DNA content is halved only in meiosis I. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis I

Answer:

c. 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.

Explanation:

Anaphase-I of meiosis-I includes the movement of homologous chromosomes to the opposite poles of the cell. This even reduces the chromosome number to half in the daughter cells formed by the end of meiosis-I. Therefore, diploid cells become haploid by the end of meiosis-I. Since chromosomes carry DNA, a reduction in chromosome number also reduces the DNA content of the cells to half in meiosis-I.

Anaphase-II in meiosis-II separates the sister chromatids of each chromosome from each other. These sister chromatids move to the opposite poles of the cell. This event further reduces the DNA content of the cell to half but the chromosome numbers are maintained.

Therefore, a cell with 2C DNA and 2n (diploid) chromosomes form two daughter cells having "C" DNA and "n" chromosomes by the end of meiosis-I. Meiosis-II in each of these daughter cells would form a total of 4 daughter cells each having "n" chromosomes and "C" DNA content.