The first phase of mitosis is prophase. During this phase the nucleus disappears. Once the nucleus has disappeared, the centrioles move from the center of the cell to different ends of it. Fibers cross and form the mitotic spindle.
Once the fibers have extended and centrioles have separated, prometaphase begins. When prometaphase begins, the nuclear membrane disappears. Kinetochores are formed in this stage when proteins connect to the centromeres. Microtubules connect to these which help the chromosomes begin moving.
During metaphase, spindle fibers work to align the chromosomes into the middle of the nucleus of the cell by creating a metaphase plate. The process allows each of the new nuclei to receive one copy of each of the chromosomes from the original.
Paired chromosomes separate during anaphase and move to opposite sides of the cell. They are separated at the kinetochores. The physical interaction of microtubules causes the cell to move into motion and begin going where it needs to go to finish mitosis.
In telophase, membranes begin to form around the new daughter nuclei. The cell will begin to separate during this phase in preparation for becoming two new cells.Learn more about Cells