Mitosis is the division of one cells contents to either side of the cell in preparation for cytokinesis which is the splitting of one cell into two identical, diploid, daughter cells. The four stages of mitosis, in the order they occur in, are: Prophase, Metaphase, Anaphase and Telophase. We can remember the order of the stages using the mnemonic 'Passing My A-level Test'. Prophase initiates cell division as the chromosomes condense, the nuclear membrane breaks down, centrioles move to either pole of the cell and the spindle polymerises. In metaphase, chromosomes align at the cell equator and attach to the spindle at their centromeres. Anaphase is the stage in which chromosomes split into sister chromatids and move to opposite poles as the microtubules contract. Finally, in Telophase the cell wall begins to form down the centre of the wall using the contractile ring, chromosomes uncoil, the nuclear membrane reforms and the spindle fibres disperse.