AP BIOLOGY

Detailed explanation-1: -The spindle is a complex microtubule-based superstructure responsible for chromosome movement and segregation during mitosis and meiosis (McIntosh and Koonce 1989; Mitchison 1989a; Rieder 1991; Hyman and Karsenti 1996; Compton 2000).

Detailed explanation-2: -The most prominent structure in a mitotic cell is the bipolar spindle (made up of microtubules and associated motor proteins), which provides the force to move chromosomes and thereby bring about their segregation. Microtubules are nucleated by the centrosome (called spindle pole body [SPB] in yeasts).

Detailed explanation-3: -The spindle fibers from the other side of the cell attach to the other sister chromatids in the chromosome. They attach at a point called the kinetochore, which is a disk or protein that is on each side of the centromere. The spindle fibers will move the chromosomes until they are lined up at the spindle equator.

Detailed explanation-4: -The segregation of the replicated chromosomes is brought about by a complex cytoskeletal machine with many moving parts-the mitotic spindle. It is constructed from microtubules and their associated proteins, which both pull the daughter chromosomes toward the poles of the spindle and move the poles apart.

Detailed explanation-5: -The spindle is a structure made of microtubules, strong fibers that are part of the cell’s “skeleton.” Its job is to organize the chromosomes and move them around during mitosis. The spindle grows between the centrosomes as they move apart.