New cells are formed by dividing, so that there are two cells were there once was one. One-celled plants and animals begin and complete their lives as single cells. (Kemp 12) Human beings and multicellular plants and animals also develop from a single cell. But after this cell grows to a certain size, it divides and forms two cells. These two cells grow and divide, forming four cells. (Zeuthen 49) The cells grow and divide over and over again, and during this process they begin to specialize. A rabbit, an elephant, an oak, or a human being finally develops from a single cell. There are two main types of cell division: (1) mitosis and (2) meiosis. (Balls 34) Most cells are produced by a process called mitosis. In mitosis, a cell divides and forms two identical daughter cells. (Prescott 102) Each daughter cell then doubles in size and becomes capable of dividing. Most one-celled plants and animals reproduce by mitosis. (Baserga Biology 56) This is also the way most cells in your body and multi-cellular plants and animals reproduce.
Mitosis in animal cells takes place in four orderly stages-- (1) prophase, (2) metaphase, (3) anaphase, and (4) telophase. (Moore 91) Most of the activity occurs in the nucleus. Between divisions, the cell grows and carries on its normal activities. During this period, the chromatin, the substance that contains the cell 's hereditary material, is scattered throughout the nucleus.
The first stage of mitosis is called the prophase stage. During early
Cited: Akkas, Nuri. Biomechanics of Cell Division. London: Plenum Press, 1987. Balls, M. and Billett, F. S. The Cell Cycle in Development and Differentiation. London: Cambridge University press, 1973. Baserga, Renato. Biochemistry of Cell Division. Springfield, Illinois: Charles C. Thomas, 1969. Baserga, Renato. The Biology of Cell Reproduction. London: Harvard University Press, 1985. Cameron, Ivan L., Padilla, George M., Zimmerman, Arthur M. Developmental Aspects of the Cell Cycle. New York: Academic Press, 1971. Garrod, D. R. Cellular Development. London: Chapman and Hall, 1973. Kemp, Roger. Cell Division and Heredity. New York: Crane, Russak, and Company, Inc., 1970. Mitchison, J. M. The Biology of the Cell Cycle. New York: Cambridge University Press, 1971. Moore, Randy and Vodopich, Darrells. Biology: Laboratory Manual. 4th ed. New York: McGraw Hill, 1996. Prescott, David M. Reproduction of Eukaryotic Cells. London: Academic Press, 1976. Zeuthen, Erik. Synchrony in Cell Division and Growth. New York: Interscience Publishers, 1964.