Question

which describes the cells at the end of meiosis i when nondisjunction occurs during meiosis ii? select all of the correct statements. a. the cells are haploid. b. the cells are diploid. c. the sister chromatids are in separate cells. d. the homologous pairs are in separate cells.

Explanation:

• Meiosis I: Homologous chromosomes separate. So, at the end of meiosis I, cells are haploid as the chromosome - number is reduced by half (homologous pairs are in separate cells). Nondisjunction in meiosis II affects sister - chromatid separation but not the fact that cells were already made haploid by meiosis I.
• Option A: Since meiosis I reduces the chromosome number (homologous pairs separate), the cells at the end of meiosis I (even if there is a meiosis II nondisjunction) are haploid.
• Option B: Meiosis I results in a reduction of chromosome number (from diploid to haploid in terms of homologous - chromosome separation). Nondisjunction in meiosis II does not change the fact that meiosis I has already occurred and reduced the chromosome number, so cells are not diploid.
• Option C: Nondisjunction in meiosis II means sister chromatids do not separate properly. So, sister chromatids are not in separate cells (this is the error of nondisjunction).
• Option D: Meiosis I is the stage where homologous pairs separate. So, at the end of meiosis I (before considering meiosis II events), homologous pairs are in separate cells.

Answer:

A. The cells are haploid.
D. The homologous pairs are in separate cells.