AP BIOLOGY

Detailed explanation-1: -The pairing of homologous chromosomes takes place in prophase I of meiosis which is separated in anaphase I leading to reduction of chromosome number to half. During anaphase II the sepsration of sister chromatids takes place.

Detailed explanation-2: -Anaphase I: In anaphase I, the attachment of the spindle fibers is complete. The homologous chromosomes are pulled apart and move towards opposite ends of the cell. Do not confuse this with the pulling apart of sister chromatids! This is the point in which reduction occurs with 23 chromosomes moving to each pole.

Detailed explanation-3: -Figure 3: During anaphase I, the homologous chromosomes are pulled toward opposite poles of the cell. During anaphase I, the microtubules disassemble and contract; this, in turn, separates the homologous chromosomes such that the two chromosomes in each pair are pulled toward opposite ends of the cell (Figure 3).

Detailed explanation-4: -The chromosomes are separated by a structure called the mitotic spindle. The mitotic spindle is made of many long proteins called microtubules, which are attached to a chromosome at one end and to the pole of a cell at the other end. The sister chromatids are separated simultaneously at their centromeres.

Detailed explanation-5: -During meiosis I, homologous chromosomes are separated. Subsequently, during meiosis II, the sister chromatids separate to produce a total of four products, each with half the number of chromosomes as the original cell.