1. Prophase. In this step, the nuclear membrane has dissolved and spindle fibres have begun to attach to the chromosomes and pull the fibres. The fibres attach onto the centromere, which acts like a belt that holds the two chromatids together.

2. Metaphase. In this phase, the spindle fibres have brought the chromosomes into the middle of the cell to for a straight line right down the center of the cell.

3. Anaphase. In this step, the spindle fibres have pulled the chromatids appart from each other and have dragged them to opposite sides of the cell. The cell begins to stretch and split.

4. Telophase. In this phase, the cell has split into two new cells and two new nucleuses have formed in each new cell. The chromatids that were split appart are now inside the new nucleuses.