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: -The two chromatids of a duplicated chromosome are held together at a region of DNA called the centromere (see figure below). Centromeres are the attachment points for microtubules, which are responsible for the guiding the movement of chromosomes during mitosis and meiosis.

Detailed explanation-3: -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. For accurate mitoses, sister chromatids must remain attached until the spindle checkpoint has been passed.

Detailed explanation-4: -Statement 1-Centromere is also called the primary constriction. Statement 2-The secondary constriction connects the satellite region of a chromosome to the rest of the chromosome. Statement 3-Nucleolus is always associated with the primary constriction.