Mitosis is a type of cell division that results in two daughter cells, each of which have the same number and kind of chromosomes as the parent cell. This process is how individual cells within an organism replicate, and is part of normal growth. Without Mitosis, the body would be unable to grow and make repairs. Mitosis should not be mistaken for meiosis, which reduces the number of chromosomes in a parent cell by half and produces four gametes rather than two identical daughter cells. Mitosis is split into four phases, prophase, metaphase, anaphase, and telophase. Cytokinesis generally accompanies mitosis, and occurs at the same time as telophase.
The chromosomes found in the nucleus of the cell begin to condense. This action makes it easier for them to pull apart later. The membrane around the nucleus also begins to deteriorate. The cell begins to form the mitotic spindle, which will play a role in the later phases.
In the latter stages of prophase, the mitotic spindle finishes and the chromosomes finish condensing. The nuclear envelope completely disappears and the chromosomes are released. Microtubules can be found on the mitotic spindle, and they begin to capture the chromosomes.
Metaphase continues the progress that was started in prophase. During metaphase, all the chromosomes are captured by the mitotic spindle. They are then lined up and paired up in the middle of the cell and are prepared to divide into two sets. The sets will be at the opposite poles of the cell. The paired chromosomes are called chromatids.
The cell checks the chromosomes to make sure they are correctly attached to the microtubules before entering anaphase. If they are, the cell will then begin anaphase. During this phase, the pairs of chromatids are pulled apart and moved to the opposite ends of the cell.
It is during telophase that the cell begins to return to normal. This takes place as cytokinesis, the division of the cell, is also taking place. During telophase, the mitotic spindle is broken down, two nuclei are formed, and the chromosomes start to spread out from their condensed form.
For the two new cells to be completely formed, cytokinesis must take place. The process of cytokinesis is slightly different for plant and animal cells. In animal cells, the mother cell is pinched and forms two cells. Plant cells are too stiff to be pinched. Instead, a structure known as the cell plate forms in the cell and divides it into the two separate cells.
All cells but sex cells replicate through mitosis. During this process, the chromosomes in the parent cell are split apart, duplicated, and then paired back up, forming two nuclei where there previously was only one. Once the genetic material is copied and the new nuclei are formed, cytokinesis begins and the cell is split into two daughter cells. This is the end of the cell cycle for the parent cell, and the beginning for the two daughter cells. It's important not to confuse mitosis with meiosis, which is the process by which a cell splits into four sex cells, or gametes, each one having half the chromosomes as the parent cell.