mitosis

CELL BIOLOGY: ON THE ORCHESTRATION OF THE MITOTIC SPINDLE: "Before embarking on mitosis, a cell duplicates its chromosomes, producing pairs of 'sister chromatids'. The members of each pair are identical. In what is known as 'prometaphase' of mitosis, these chromatids become tethered to the spindle, such that one member of each pair is attached to a bundle of microtubules emanating from one pole, and the other member is connected to the other pole. 'Kinetochores' are the microtubule landing pads on chromosomes(3). A tug-of-war ensues, driven by the addition or loss of tubulin (that is, microtubule polymerization or depolymerization) at the kinetochores. This tug-of-war results in chromosomes becoming aligned during metaphase of mitosis, such that each sister faces its final destination. Finally, 'anaphase' begins when the glue holding sisters together is dissolved, and they take off towards opposite spindle poles.(2)"