During anaphase, the centromeres of sister chromatids split allowing them to separate and become individual chromosomes, moving to opposite poles of the cell.
The centromeres of sister chromatids split apart during anaphase, the third phase of mitosis. This phase is characterized by the separation of sister chromatids, as the cohesin proteins degrade and centromeres divide, allowing the chromatids, now individual chromosomes, to move to opposite poles of the cell.
These events occur as the spindle fibers attached to each chromatid shorten, functioning akin to a fishing line being reeled in. Additionally, the cell elongates due to the sliding of non-kinetochore microtubules against each other at the metaphase plate. The result of anaphase is two sets of chromosomes at each pole, preparing the cell to enter the next phase, which is telophase.