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.

Detailed explanation-2: -Sister chromatids are physically held together by cohesin, which is a protein complex consisting of four core subunits (Fig.

Detailed explanation-3: -A sister chromatid refers to the identical copies (chromatids) formed by the DNA replication of a chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said to be ‘one-half’ of the duplicated chromosome. A pair of sister chromatids is called a dyad.

Detailed explanation-4: -The sister chromatids are pairs of identical copies of DNA joined at a point called the centromere.

Detailed explanation-5: -After DNA is replicated each chromosome consists of paired sister chromatids held together by cohesin.