AP BIOLOGY

Detailed explanation-1: -The two “sister” chromatids are joined at a constricted region of the chromosome called the centromere. During cell division, spindle fibers attach to the centromere and pull each of the sister chromatids to opposite sides of the cell. Soon after, the cell divides in two, resulting in daughter cells with identical DNA.

Detailed explanation-2: -During DNA duplication in the S phase, each chromosome is replicated to produce two identical copies, called sister chromatids, that are held together at the centromere by cohesin proteins. Cohesin holds the chromatids together until anaphase II.

Detailed explanation-3: -Cohesin forms rings that hold the sister chromatids together, whereas condensin forms rings that coil the chromosomes into highly compact forms.

Detailed explanation-4: -Sister Chromatids Are Joined Together at Centromeres In addition to their kinetochore-related function, centromeres perform another essential role in mitosis by serving as the sites of sister chromatid cohesion.

Detailed explanation-5: -Metaphase. During metaphase, spindle fibers attach to the centromere of each pair of sister chromatids (see Figure below). The sister chromatids line up at the equator, or center, of the cell. This is also known as the metaphase plate.