AP BIOLOGY

Detailed explanation-1: -Nondisjunction can occur during anaphase of mitosis, meiosis I, or meiosis II. During anaphase, sister chromatids (or homologous chromosomes for meiosis I), will separate and move to opposite poles of the cell, pulled by microtubules.

Detailed explanation-2: -Nondisjunction, in which chromosomes fail to separate equally, can occur in meiosis I (first row), meiosis II (second row), and mitosis (third row). These unequal separations can produce daughter cells with unexpected chromosome numbers, called aneuploids.

Detailed explanation-3: -Nondisjunction in Meiosis 1 vs 2 Failure of homologous chromosomes to separate towards the poles during anaphase 1 is known as nondisjunction in meiosis 1. Failure of sister chromatids to separate towards the poles during anaphase 2 in meiosis is known as nondisjunction in meiosis 2.

Detailed explanation-4: -When nondisjunction occurs in meiosis II, cells divide normally during anaphase I (homologous chromosomes separate correctly), but sister chromatids fail to separate during anaphase II (as seen in the diagram above, on the left). This again results in four possible haploid gametes.

Detailed explanation-5: -Explanation: Chromosome disjunction is the splitting up of paired of chromosomes. This occurs in anaphase I and anaphase II where the homologous chromosomes split and the sister chromatids split, respectively.