During which phase of mitosis do chromosomes align in the center of the cell?

During mitosis, the phase in which chromosomes align in the center of the cell is known as metaphase. During this stage, the chromosomes, which have already been replicated and condensed, line up along the metaphase plate at the cell's equatorial plane. This alignment is crucial for the subsequent separation of sister chromatids, ensuring that each daughter cell receives an identical set of chromosomes.

The alignment occurs due to the action of the mitotic spindle, which is composed of microtubules that attach to the centromeres of the chromosomes through structures called kinetochores. This precise arrangement is a key step in ensuring accurate cellular division. In contrast, the other phases involve different activities: prophase involves the condensing of chromatin into visible chromosomes, anaphase is when sister chromatids are pulled apart to opposite poles of the cell, and telophase is the period where the chromosomes de-condense and the nuclear envelope reforms.