What is "cell division"

Division \Di*vi"sion\, n. [F. division, L. divisio, from dividere. See Divide.]

1. The act or process of diving anything into parts, or the state of being so divided; separation.

   I was overlooked in the division of the spoil.
   --Gibbon.

2. That which divides or keeps apart; a partition.

3. The portion separated by the divining of a mass or body; a distinct segment or section.

   Communities and divisions of men.
   --Addison.

4. Disunion; difference in opinion or feeling; discord; variance; alienation.

   There was a division among the people.
   --John vii. 43.

5. Difference of condition; state of distinction; distinction; contrast.
   --Chaucer.

   I will put a division between my people and thy people.
   --Ex. viii. 23.

6. Separation of the members of a deliberative body, esp. of the Houses of Parliament, to ascertain the vote.

   The motion passed without a division.
   --Macaulay.

7. (Math.) The process of finding how many times one number or quantity is contained in another; the reverse of multiplication; also, the rule by which the operation is performed.

8. (Logic) The separation of a genus into its constituent species.

9. (Mil.)

   1. Two or more brigades under the command of a general officer.

   2. Two companies of infantry maneuvering as one subdivision of a battalion.

   3. One of the larger districts into which a country is divided for administering military affairs.

10. (Naut.) One of the groups into which a fleet is divided.

11. (Mus.) A course of notes so running into each other as to form one series or chain, to be sung in one breath to one syllable.

12. (Rhet.) The distribution of a discourse into parts; a part so distinguished.

13. (Biol.) A grade or rank in classification; a portion of a tribe or of a class; or, in some recent authorities, equivalent to a subkingdom.

    Cell division (Biol.), a method of cell increase, in which new cells are formed by the division of the parent cell. In this process, the cell nucleus undergoes peculiar differentiations and changes, as shown in the figure (see also Karyokinesis). At the same time the protoplasm of the cell becomes gradually constricted by a furrow transverse to the long axis of the nuclear spindle, followed, on the completion of the division of the nucleus, by a separation of the cell contents into two masses, called the daughter cells.

    Long division (Math.), the process of division when the operations are mostly written down.

    Short division (Math.), the process of division when the operations are mentally performed and only the results written down; -- used principally when the divisor is not greater than ten or twelve.

    Syn: compartment; section; share; allotment; distribution; separation; partition; disjunction; disconnection; difference; variance; discord; disunion.

n. a process by which a cell divides into two cells

n. the process in reproduction and growth by which a cell divides to form daughter cells [syn: cellular division]

Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle. In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell ( mitosis), and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half, to produce haploid gametes ( meiosis). Meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions: homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in sexually reproducing organisms at some point in their life cycle, and both are believed to be present in the last eukaryotic common ancestor. Prokaryotes also undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication.

For simple unicellular organisms such as the amoeba, one cell division is equivalent to reproduction – an entire new organism is created. On a larger scale, mitotic cell division can create progeny from multicellular organisms, such as plants that grow from cuttings. Cell division also enables sexually reproducing organisms to develop from the one-celled zygote, which itself was produced by cell division from gametes. And after growth, cell division allows for continual construction and repair of the organism. A human being's body experiences about 10 quadrillion cell divisions in a lifetime.

The primary concern of cell division is the maintenance of the original cell's genome. Before division can occur, the genomic information that is stored in chromosomes must be replicated, and the duplicated genome must be separated cleanly between cells. A great deal of cellular infrastructure is involved in keeping genomic information consistent between "generations".