Final answer:
During anaphase of the mitotic phase, mitotic spindles pull the sister chromatids apart and move them to opposite poles of the cell.
Step-by-step explanation:
In the mitotic phase of the cell division cycle, specifically during anaphase, the mitotic spindles pull the sister chromatids apart. Once the sister chromatids, now called chromosomes, are separated, they are moved to the opposite poles of the cell. The role of the mitotic spindle is crucial as it is composed of microtubules that emanate from the centrioles, and these structures facilitate the arrangement and movement of chromosomes during mitosis. Following anaphase, during telophase, the chromosomes begin to decondense and the nuclear envelopes re-form around the chromosomes, concluding the division of the nucleus.