What occurs during anaphase of mitosis?

During anaphase of mitosis, sister chromatids separate and move towards opposite ends of the cell.

Anaphase is the fourth phase of mitosis, the process by which a single cell divides into two identical daughter cells. This phase is characterised by the separation of sister chromatids, which are identical copies of a single chromosome. These chromatids are pulled apart by the spindle fibres, a network of protein structures that extend from each end of the cell.

At the beginning of anaphase, each pair of sister chromatids is located at the cell's equator, attached to the spindle fibres by a structure called the centromere. The centromeres then split, allowing the sister chromatids to separate. This separation is driven by the shortening of the spindle fibres, which effectively pulls the chromatids towards opposite ends of the cell.

This movement ensures that each daughter cell will receive an identical set of chromosomes. It is a critical step in cell division, as any errors can lead to genetic abnormalities in the daughter cells. For example, if a pair of sister chromatids fails to separate properly, one daughter cell may end up with an extra chromosome, while the other may lack that chromosome entirely. This condition, known as aneuploidy, can cause a variety of health problems, including cancer and developmental disorders.

In summary, anaphase is a crucial stage of mitosis that ensures the equal distribution of genetic material between the two daughter cells. It is characterised by the separation of sister chromatids, which are pulled towards opposite ends of the cell by the spindle fibres.