In biology, cell division is a process in which one parent cell is split into two or more daughter cells. There are two types of cell division: meiosis and mitosis. Mitosis occurs when the mother cell divides into two new genetically identical daughter cells that have the same number of chromosomes as the parent cell or nucleus. During mitosis, old cells in the organism are replaced with new cells, which is how the organism essentially functions.
There are four main phases of mitosis: prophase, metaphase, anaphase, and telophase. The DNA replicates in a process known as interphase; after interphase, the process of prophase occurs. Prophase is the longest phase of mitosis, during which the chromatin condenses into chromosomes and the mitotic spindle is formed; the duplicated DNA separates into two sister chromatids. Some scientist agree that the process of prophase can be separated into early prophase and late prophase or prometaphase.
During metaphase, the chromosomes are fully condensed and they line up at the metaphase plate, in the center of the cell. In anaphase, the replicated chromosomes or the centromeres are separated into two sister chromatids and they move towards the opposite poles of the cell. Finally, telophase is the last phase of mitosis in which the chromosomes at the ends of the cell begin to decondense, the mitotic spindle is broken down and the cytoplasm begins to divide with the purpose of forming two new identical daughter cells—a process known as cytokinesis.