Human cell division is the process by which cells within the human body divide their chromosomes and split in to two daughter cells to sustain the organisms in which they reside. Cell division is also how humans, and the organs within them, grow. The process by which somatic, or body, cells divide is called mitosis. The steps that humans and animals undergo during mitosis are identical. There are some differences in the processes of human cell division and cell division in plants, although the major steps are the same.
Mitosis consists of four phases. During prophase, chromosomes condense, winding tightly around a mitotic spindle. The chromosomes, once invisible, can be seen under a microscope during most of mitosis. The mitotic spindle forms on the outside of the cell during human cell division, and around the nucleus in plants undergoing division. In plants, a cytoskeletal band also forms during prophase.
The second phase of mitosis is metaphase. During this phase, the membrane around the nucleus disappears and chromosomes move into the middle of the cell. The chromosomes split in half, giving the cell twice as many chromosomes as it started with. The steps of metaphase in human cell division are almost identical to that in plant cell division. The one exception is that the cytoskeletal band that formed during plant prophase disappears.
During anaphase, the chromosomes in the mother cell spread apart. Each group of chromosomes moves in an opposite direction toward the outside edges in preparation for cell division. There are no major differences in how anaphase is carried out in plant and animal cells.
Telophase is the last stage of mitosis. At the beginning of the phase, two sets of chromosomes appear at polar ends of the cell. Two nuclei begin to appear around each set of chromosomes and the chromosomes begin to unwind from the mitotic spindle and disappear. In human cell division, rings that will serve as the cell membrane in the daughter cells form around the middle of the cell. In plants, cytoskeletal proteins that will serve as the new cell wall appear.
Cytokinesis, which occurs during anaphase and telophase, is critical to cell division. The cytoplasm and organelles are divided during cytokinesis. In humans, the original cell is split in the center during cytokinesis, the new membrane is fused, and the nuclei separate. In plants, a new cell wall grows to form the two daughter cells.