In biology, fission is the subdivision of a body, population, or species into parts and the regeneration of those parts into separate individuals.[1][2][3] Binary fission, or prokaryotic fission, is a form of asexual reproduction and cell division used by all prokaryotes, some protozoa, and some organelles within eukaryotic organisms. This process results in the reproduction of a living prokaryotic cell by division into two parts that each have the potential to grow to the size of the original cell.
Mitosis and cytokinesis are not the same as binary fission. To be specific, binary fission cannot be divided into prophase, metaphase, anaphase, and telophase because prokaryotes have no nucleus and no centromeres. The ability of some multicellular animals, such as echinoderms and flatworms, to regenerate two whole organisms after having been cut in half, is also not the same as binary fission. Neither is vegetative reproduction of plants.
Process
Binary fission begins with DNA replication. DNA replication starts from an origin of replication, which opens up into a replication bubble (note: prokaryotic DNA replication usually has only one origin of replication, whereas eukaryotes have multiple origins of replication). The replication bubble separates the DNA double strand, with each strand acting as template for synthesis of a daughter strand by semiconservative replication, until the entire prokaryotic DNA is duplicated.
Each circular DNA strand then attaches to the cell membrane. The cell elongates, causing the DNA to separate.
Cell division in bacteria is controlled by the FtsZ, a collection of about a dozen proteins that collect around the site of division. There, they direct assembly of the division septum. The cell wall and plasma membrane starts growing transversely from near the middle of the dividing cell. This separates the parent cell into two nearly equal daughter cells, each having a nuclear body.[4]
The cell membrane then invaginates (grows inward) and splits the cell into two daughter cells, separated by a newly grown cell plate.
Use by eukaryotic organelles
The use of binary fission by Eukaryotic organelles such as mitochondria, chloroplasts, and peroxisomes is not yet clear.
References
- ^ Carlson, B. M. (2007). Principals of regenerative biology. Elsevier Academic Press. p. 379. ISBN 0123694396.
- ^ Boulay, R. L.; Galarza, J. A.; Che, B.; Hefetz, A.; Lenoir, A.; van Oudenhove, L.; Cerda, X. (2010). "Intraspecific competition affects population size and resource allocation in an ant dispersing by colony fission". Ecology. 91 (11): 3312–3321. doi:10.1890/09-1520.1.
- ^ Hubbell, S. (2003). "Modes of speciation and the lifespans of species under neutrality: a response to the comment of Robert E. Ricklefs". Oikos. 100 (1): 193–199. doi:10.1034/j.1600-0706.2003.12450.x.
- ^ Weiss, David S. (2004), "Bacterial cell division and the septal ring", Molecular Microbiology, 54 (3): 588–597, doi:10.1111/j.1365-2958.2004.04283.x, PMID 15491352