Cells divide for the purposes of reproduction, replacement of lost or dead cells and to promote growth of the structure in which they are located. Only the first of these reasons applies to single-celled organisms, but the others are essential to the efficient functioning of a multicellular body.Continue Reading
Reproduction is the oldest, and perhaps the simplest, reason cells divide. In reproductive fission, one cell typically grows larger than usual, duplicates its organelles and any internal structures and then divides into two nearly identical cells. Among microbes, this process, called mitosis, is one of the most common means for reproduction. In multicellular organisms, such as plants and animals, germ-line cells undergo a special form of cell division known as meiosis.
Plant and animal cells also divide for reasons related to the needs of the organism. When a skin cell is damaged, for instance, the cells near the site of the damage often divide as a way of replacing the lost tissue. Some tissues, such as the lining of the stomach, are subject to high levels of environmental attrition and must be replaced in this way continuously. Cells also divide as a way of enlarging the structures they are building. The exact timing and sequence of this division largely determines the shape and size of the structure being built.Learn more about Cells