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: -Powering chromosome movement (microtubules) 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.

Detailed explanation-3: -In mitotic cells and in meiosis II, microtubules attach to kinetochores in a way that means the sister chromatids are pulled apart. During meiosis I, on the other hand, they attach to kinetochores in a manner so the homologous chromosomes are pulled apart. Miller et al.

Detailed explanation-4: -They function both to determine cell shape and in a variety of cell movements, including some forms of cell locomotion, the intracellular transport of organelles, and the separation of chromosomes during mitosis.

Detailed explanation-5: -During metaphase of meiosis I and II, microtubules form a pointed and elongated bipolar spindle, which then shortens during anaphase. In addition, the microtubule density shifts from the spindle poles to the midzone between the separating chromosomes.