Not to be confused with cellular differentiation.
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).
Cell division gives rise to genetically identical cells in which the total number of chromosomes is maintained.
In general, mitosis (division of the nucleus) is preceded by the S stage of interphase (during which the DNA is replicated) and is often followed by telophase and cytokinesis; which divides the cytoplasm, organelles and cell membrane of one cell into two new cells containing roughly equal shares of these cellular components.
The different stages of Mitosis all together define the mitotic (M) phase of an animal cell cycle—the division of the mother cell into two daughter cells genetically identical daughter cells.
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 the process of sexual reproduction at some point in their life cycle.
Both are believed to be present in the last eukaryotic common ancestor.
While binary fission may be the means of division by most prokaryotes, there are alternative manners of division, such as budding, that have been observed.
All cell divisions, regardless of organism, are preceded by a single round of DNA replication.
On a larger scale, mitotic cell division can create progeny from multicellular organisms, such as plants that grow from cuttings.
After growth, cell division by mitosis allows for continual construction and repair of the organism.
The human 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.
Cell division in Bacteria
Bacterial cell division happens through binary fission or budding.
The Divisome is a protein complex in bacteria that is responsible for cell division, constriction of inner and outer membranes during division, and peptidoglycan (PG) synthesis at the division site.
A tubulin like protein, FtsZ plays a critical role in formation of a contractile ring for the cell division.
Cell Division in Eukaryote
See also: Alternation of generations
Cell division in eukaryote is much more complicated than prokaryote.
A primitive form of cell division is also found which is called amitosis.
The amitotic or mitotic cell division is more atypical and diverse in the various groups of organisms such as protists (namely diatoms, dinoflagellates etc) and fungi.
In mitotic metaphase (see below), typically the chromosomes (each with 2 sister chromatid that they developed due to replication in the S phase of interphase) arranged and sister chromatids split and distributed towards daughter cells.
In meiosis, typically in Meiosis-I the homologous chromosomes are paired and then separated and distributed into daughter cells.
Meiosis-II is like mitosis where the chromatids are separated.
In human and other higher animals and many other organisms, the meiosis is called gametic meiosis, that is the meiosis gives rise to gametes.
Whereas in many groups of organisms, especially in plants (observable in lower plants but vestigial stage in higher plants), the meiosis gives rise to the kind of spores that germinate into haploid vegetative phase (gametophyte).
This kind of meiosis is called sporic meiosis.
Phases of eukaryotic cell division
Due to their structural differences, eukaryotic and prokaryotic cells do not divide in the same way.
Also, the pattern of cell division that transforms eukaryotic stem cells into gametes (sperm cells in males or egg cells in females), termed meiosis, is different from that of the division of somatic cells in the body.
Image of the mitotic spindle in a human cell showing microtubules in green, chromosomes (DNA) in blue, and kinetochores in red.
Multicellular organisms replace worn-out cells through cell division.
In some animals, however, cell division eventually halts.
The cell is then referred to as senescent.
This shortening has been correlated to negative effects such as age related diseases and shortened lifespans in humans.
Cancer cells, on the other hand, are not thought to degrade in this way, if at all.
- Binary fission
- Cell biology
- Cell fusion
- Cell growth
- Cyclin-dependent kinase
- Labile cells, cells that constantly divide
Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Cell division.