Mitosis is the process by which a diploid parent cell produces two diploid daughter cells. It is also known as cell division.
Both animal and plants are multicellular organisms and for them, mitosis is a way to replace old worn out cells, or for growth. The DNA must first be replicated before this process begins. This occurs during the stage known as interphase during the cell cycle. Specifically, it occurs during the S phase of interphase. The duplicated chromosomes are called sister chromatids, which are held together by a centromere. Once interphase is completed, mitosis can begin. It is important to note that a cell spends most of its time in interphase and only about 10 percent of its time actually going through the mitotic phase.
The stages of mitosis are prophase, prometaphase, metaphase, anaphase and telophase. At the end of interphase, the chromosomes have duplicated and the centrosome has also duplicated. However, in the animal cell, each centrosome contains a pair of centrioles. Plants do not have centrioles. Centrioles are involved in helping the spindle to form in an animal cell but although plants lack this organelle, they still are able to form a spindle.
Mitosis begins and prophase is the first stage when the nucleoli disappear and a mitotic spindle forms from the centrosomes which then move apart forming a spindle apparatus between them.
Next is prometaphase, a time where the chromatids attach to the spindle via their centromeres.
During metaphase, the chromatids align themselves along the metaphase plate.
In anaphase, the centromeres divide and the chromatids are pulled to opposite poles, becoming single chromosomes once again.
At telophase, daughter nuclei reform around each set of chromosomes forming two new daughter cells.
Cytokinesis occurs after mitosis and in plants, a new cell plate forms to separate the two daughter cells from each other. This is formed by vesicles that were produced in the Golgi apparatus and they link together to form a cell plate which eventually becomes part of the cell wall. In animal cells, a cleavage furrow forms and the cell membrane pinches inward until two new cells are produced.