How are sister chromatids separated during mitosis?

Sister chromatids are separated during mitosis by the pulling action of spindle fibres in the anaphase stage.

Mitosis is a process of cell division that results in two genetically identical daughter cells. It is a crucial part of the cell cycle and is divided into several stages: prophase, metaphase, anaphase, and telophase. The separation of sister chromatids occurs during the anaphase stage.

In the early stages of mitosis, the DNA in the cell's nucleus is replicated to form two identical copies. These copies, known as sister chromatids, are held together at a region called the centromere. As the cell enters metaphase, the sister chromatids align at the cell's equator, and spindle fibres, which are protein structures, attach to the centromeres.

The real action begins in anaphase. The centromeres split, and the spindle fibres begin to shorten and pull the sister chromatids apart. This pulling action is facilitated by motor proteins that 'walk' along the spindle fibres, effectively dragging the chromatids towards opposite ends of the cell. This ensures that each new cell will receive one copy of each chromosome.

By the end of anaphase, the sister chromatids have been successfully separated and are now considered individual chromosomes. They are pulled to opposite poles of the cell, ready for the final stage of mitosis, telophase, where two new nuclei form around these chromosomes.

The separation of sister chromatids is a critical process in cell division, ensuring that each new cell receives an exact copy of the genetic material. Any errors in this process can lead to genetic abnormalities in the daughter cells, highlighting the importance of the precise and coordinated actions of the spindle fibres and motor proteins during anaphase.