Final answer:
Prometaphase is the stage of mitosis where the movement of sister chromatids occurs due to the attachment of mitotic spindle microtubules. This movement helps align the sister chromatids at the metaphase plate.
Step-by-step explanation:
Prometaphase is the stage of mitosis where the movement of sister chromatids occurs. During prometaphase, mitotic spindle microtubules from opposite poles attach to each sister chromatid at the kinetochore. This attachment allows the sister chromatids to be pulled back and forth, eventually aligning them at the metaphase plate. In anaphase, the connection between the sister chromatids breaks down, and the microtubules pull the chromosomes toward opposite poles.