At what point during mitosis do the chromosomes (chromatids) separate?

During mitosis, the separation of the chromosomes, which are duplicated and held together at their centromeres, occurs during anaphase. In this phase, the centromeres split, allowing the sister chromatids to move toward opposite poles of the cell. This action is facilitated by the spindle fibers that pull the chromatids apart.

Anaphase is the crucial stage in ensuring that each daughter cell will receive an identical set of chromosomes, making the distribution of genetic material accurate as the cell prepares to divide. The earlier phases, such as prophase and metaphase, are focused on the organization and alignment of chromosomes without actual separation, while telophase marks the end of nuclear division and the return to de-condensed chromatin, following the complete separation of the chromatids.