Mitosis is a cell division that occurs in animal cells where each mother cell divides into 2 daughter cells. The number of chromosomes in the mother cell is identical to that in each resulting daughter cell. This is why mitosis is sometimes called an ” Identical Reproduction of Cells”.
Below you find the phases of the mitosis and a description of the main events taking place in each. Keep in mind that interphase is not a phase of mitosis, it is just a preparatory phase that precedes mitosis. This phase is very important at the end of which, each chromosome will change to have two identical sister chromatids after duplicating the DNA molecule making up the original chromatid.
Chromosomes, in the form of chromatin, will duplicate their chromatids ( DNA replication)
|Prophase||1- Chromatin condense into well defined chromosomes.
2- Each chromosome is made up of 2 chromatids joined by a centromere.
3- The centrosomes duplicate and transform into asters.
4- The nuclear membrane disappears.
5- A spindle of fibers forms ( achromatic spindle).
|Metaphase||Chromosomes move to the center of the cell and line up along the equator od the cell forming the “Equatorial Plate”.|
|Anaphase||1- The centromeres split and the sister chromatids separate. Each chromosome is now formed of one chromatid with a centromere.
2- Sister chromatids move towards opposite poles of the cell . This is called “Polar Ascension”.
|Telophase||1- The chromosomes de-condense and go back to the chromatin state ( tall and thin).
2- The asters become centrosomes.
3-A new nuclear membrane forms.
4- All the spindle fibers break down and disappear.
5- The cytoplasm of the mother cell will be cleaved in half, and the cell membrane will finish its constriction at the middle of the cell to divide the mother cell into two separate daughter cells that enter into a new interphase.