Final answer:
During anaphase, sister chromatids are separated by the shortening of kinetochore microtubules, and the cell is elongated by the sliding apart of nonkinetochore microtubules, which push the poles of the cell apart with the help of motor proteins.
Step-by-step explanation:
During anaphase, the cell undergoes significant changes that lead to the separation of sister chromatids and the elongation of the cell. The kinetochore microtubules attached to the chromatids shorten, which pulls the sister chromatids apart toward the opposite poles. Meanwhile, the nonkinetochore microtubules, also known as polar microtubules, work to lengthen the cell. These polar microtubules overlap at the cell's equator and slide past each other. This is facilitated by motor proteins like dynein, which use the energy from ATP hydrolysis to move along the microtubules, pushing the poles of the cell apart and thus elongating the cell.
As the kinetochore microtubules pull the chromatids, they disassemble at their minus ends, which are anchored at the centrosomes or microtubule organizing centers (MTOCs). The force generated by this disassembly, along with the sliding mechanism of the nonkinetochore microtubules, is responsible for the visible elongation of the cell during anaphase. These processes ensure that each new daughter cell will have a complete and identical set of chromosomes once cytokinesis (the final separation of the two new cells) is complete.