describe the process of binary fission
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In biology, fission is the subdivision of a body, population, or species into parts and the regeneration of those parts into separate individuals. 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.
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, with each strand acting as template for synthesis of a daughter strand by semiconservative replication, until the entire prokaryotic DNA is duplicated.
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.
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
A binary asteroid is a system of two asteroids orbiting their common center of mass, in analogy with binary stars. 243 Ida was the first binary asteroid to be identified when the Galileo spacecraft did a flyby in 1993. Since then numerous binary asteroids have been detected.
When both binary asteroids are similar in size, they are sometimes called "binary companions", "double asteroids" or "doublet asteroids". A good example of a true binary companion is the 90 Antiope system. Binary asteroids with a small satellite, called a "moonlet", have been more commonly observed (see 22 Kalliope, 45 Eugenia, 87 Sylvia, 107 Camilla, 121 Hermione, 130 Elektra, 243 Ida, 283 Emma, 379 Huenna, etc.). They are also called high-size ratio binary asteroid systems.
Several theories have been posited to explain the formation of binary asteroid systems. Recent work suggests that most of them have a significant macro-porosity (a "rubble-pile" interior). The satellite orbiting around large main-belt asteroids such as 22 Kalliope, 45 Eugenia or 87 Sylvia could have formed by disruption of a parent body after impact or fission after an oblique impact. Transneptunian binary asteroids may have formed during the formation of the solar system by mutual capture or three-body interaction. Near-Earth asteroids which orbit in the inner part of our solar system may have split by tidal disruption after a close encounter with a terrestrial planet. A possible explanation for the relatively greater occurrence of binary asteroids near or inside of Earth's orbit was described in the journal Nature (10 June 2008): this theory states that when solar energy (see YORP effect) spins a â€œrubble pileâ€� asteroid to a sufficiently fast rate, material is thrown from the asteroidâ€™s equator. This process also exposes fresh material at the poles of the asteroid.
Yeasts are eukaryotic micro-organism s classified in the kingdom Fungi, with the 1,500 species currently described estimated to be only 1% of all yeast species. Most reproduce asexual ly by budding, although a few do so by binary fission. Yeasts are unicellular, although some species
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Answers:Advantage 1. Reproductive cycle is small 2. its a simple process without the involvement of 2 parents Disadvantage 1. no evolution occurs 2. the daughter is exact copies of the parent
Answers:(1) Binary fission is the process by which prokaryotes divide into two identical daughter cells, which can eventually grow to the same size as the original parent cell. Such reproduction is characterized by exponential growth phases. A disadvantage is that there is little or no genetic variation, so habitat adaptation is not as rapid as would be expected with eukaryotic sexual reproduction. (2) Budding (also called burgeoning) is the formation of a new organism by the protrusion of part of another organism. This is very common in plants and fungi, but may be found in some animals as well, such as the Hydra. Usually, the protrusion stays attached to the primary organism for a while, before becoming free. The new organism is naturally genetically identical to the primary one (a clone), so, as with binary fission, there is not as much genetic variation in offspring as occurs with sexual reproduction. (3) Spore formation. A spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many plants, algae, fungi and some protozoans. Spores are usually haploid and unicellular and are produced by meiosis in the sporophyte. Once conditions are favorable, the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which eventually goes on to produce gametes. Two gametes fuse to create a new sporophyte. This cycle is known as alternation of generations, but a better term is "biological life cycle", as there may be more than one phase and so it cannot be a direct alternation. Haploid spores produced by mitosis (known as mitospores) are used by many fungi for asexual reproduction. A chief difference between spores and seeds as dispersal units is that spores have very little stored food resources compared with seeds. Because spores contain so few nutrition stores, they are not as nurturing to a developing individual as a seed, egg, or placenta. (4) Fragmentation or Clonal Fragmentation is a form of asexual reproduction or cloning where an organism is split into fragments. The splitting may or may not be intentional. Each of these fragments develop into mature, fully grown individuals that are a clone of the original organism. If the organism is split any further the process is repeated. Fragmentation is caused by mitosis. Meiosis is not involved in fragmentation. Fragmentation is seen in many organisms such as molds, some annelid worms, and starfish. Binary fission of single-celled organisms such bacteria, protozoa and many algae is a type of fragmentation. Molds, yeast, and mushrooms, all of which are part of the Fungi kingdom, produce tiny filaments called hyphae. These hyphae obtain food and nutrients from the body of other organisms to grow and fertilize. Then a piece of hyphae breaks off and grows into a new individual and the cycle continues. As with other types of asexual reproduction, fragmentation does not provide any genetic variation in offspring, and does not allow for any hybridization or heterosis. Thus, as with all forms of asexual reproduction, adaptation to new environemental conditions is not as rapid as with sexual reproduction. (5) Vegetative reproduction is a type of asexual reproduction found in plants, and is also called vegetative propagation or vegetative multiplication. It is a process by which new plant "individuals" arise or are obtained without production of seeds or spores. It is both a natural process in many plant species (as well as non-plant organisms such as bacteria and fungi) and one used or encouraged by horticulturists to obtain quantities of economically valuable plants. As with other types of asexual reproduction, vegetative reproduction does not provide any genetic variation in offspring, and does not allow for any hybridization or heterosis. Thus, as with all forms of asexual reproduction, adaptation to new environemental conditions is not as rapid as with sexual reproduction.
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