Binary fission


Binary fission

Binary fission is the form of asexual reproduction and cell division used by prokaryotic organisms (such as bacteria or archea). This process results in the reproduction of a living prokaryotic cell by division into two parts which each have the potential to grow to the size of the original cell.

Mitosis and cytokinesis are not the same as binary fission. 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 growing plants from cuttings.

Genetic effects

Binary fission is asexual; the organism splits directly into two equal-sized offspring, each with a copy of the parent's genetic material. Binary fission is the usual type of reproduction in prokaryotes, the more familiar of which are known as bacteria.

Organisms that reproduce through binary fission generally have exponential growth phases. "Escherichia coli" cells are able to divide every 20 minutes under optimum conditions.

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 1 origin of replication, whereas eukaryotes have multiple origins of replication). The replication bubble separates the DNA double strand, each strand acts as template for synthesis of a daughter strand by semiconservative replication, until the entire prokaryotic DNA is duplicated.

After this replicational process, cell growth occurs.

Each circular DNA strand then attaches to the cell membrane. The cell elongates, causing the two chromosomes to separate.

Cell division in bacteria is controlled by the septal ring, 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. The dividing septum originates centripetally and separates the parent cell into two nearly equal daughter cells ,each having a nuclear body [http://www.blackwell-synergy.com/links/doi/10.1111/j.1365-2958.2004.04283.x/pdf Blackwell Synergy - Cookie Absent ] ]

The cell membrane then invaginates (grows inwards) and splits the cell into two daughter cells, separated by a newly grown cell plate.

Use by eukaryotic organelles

Eukaryotic organelles such as mitochondria and chloroplasts also reproduce within the eukaryotic cell by binary fission. How they are allotted to one descendant cell or the other during mitosis and cytokinesis is not yet clear.

References


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Look at other dictionaries:

  • binary fission — n reproduction of a cell by division into two approximately equal parts compare MULTIPLE FISSION * * * fission of a cell in which the cell divides into two approximately equal daughter parts …   Medical dictionary

  • binary fission — binary fission. См. деление надвое. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • binary fission — n. asexual reproduction in protists by a splitting of the cell into two approximately equal parts …   English World dictionary

  • binary fission — Biol. fission into two organisms approximately equal in size. Cf. multiple fission. [1895 1900] * * * ▪ cell division       asexual reproduction by a separation of the body into two new bodies. In the process of binary fission, an organism… …   Universalium

  • binary fission — noun : reproduction of a cell by division into two approximately equal parts the binary fission of protozoans * * * Biol. fission into two organisms approximately equal in size. Cf. multiple fission. [1895 1900] * * * binary fission noun… …   Useful english dictionary

  • binary fission — dvidalis dalijimasis statusas T sritis fizika atitikmenys: angl. binary fission; bipartition vok. binäre Spaltung, f rus. деление на две части, n pranc. bipartition, f; fission binaire, f …   Fizikos terminų žodynas

  • binary fission — noun Date: 1897 reproduction of a cell by division into two approximately equal parts < the binary fission of protozoans > …   New Collegiate Dictionary

  • binary fission — A form of asexual reproduction in which a cell, or organism divides into approximately equal parts; see transverse fission …   Dictionary of invertebrate zoology

  • binary fission — bi′nary fis′sion n. cbl fission into two organisms roughly equal in size …   From formal English to slang

  • binary fission — Asexual reproduction in which a cell or an organism separates into two cells …   Dictionary of microbiology


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