Biology, asked by bharathmohank108, 11 months ago

आर्की बैक्टीरिया मे क्या नही पाया जाता

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Archaea

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"Archea" redirects here. For the geologic eon, see Archean. For the spider genus, see Archaea (spider). For the spider family, see Archaeidae. For the prefix "archae-", see List of commonly used taxonomic affixes.

For the journal, see Archaea (journal).

Archaea (/ɑːrˈkiːə/ (About this soundlisten) or /ɑːrˈkeɪə/ ar-KEE-ə or ar-KAY-ə) (singular archaeon) constitute a domain of single-celled organisms. These microorganisms are prokaryotes, and have no cell nucleus. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this classification is outmoded.[6]

Archaea

Temporal range: 3.5–0 Ga

Had'nArcheanProterozoicPha.

Paleoarchean or perhaps Eoarchean – recent

Halobacteria.jpg

Halobacterium sp. strain NRC-1,

each cell about 5 μm long

Scientific classification e

Domain:

Archaea

Woese, Kandler & Wheelis, 1990[1]

Subkingdoms[4] and phyla[5]

"Euryarchaeota" Woese et al. 1990

"Methanopyri" Garrity and Holt 2002

"Methanococci" Boone 2002

"Eurythermea" Cavalier-Smith 2002[2]

"Neobacteria" Cavalier-Smith 2002[2]

"DPANN"

"ARMAN"

"Micrarchaeota" Baker et al. 2010

"Parvarchaeota" Rinke et al. 2013

"Aenigmarchaeota" Rinke et al. 2013

"Diapherotrites" Rinke et al. 2013

"Nanoarchaeota" Huber et al. 2002

"Nanohaloarchaeota" Rinke et al. 2013

"Pacearchaeota" Castelle et al. 2015

"Woesearchaeota" Castelle et al. 2015

"Proteoarchaeota" Petitjean et al. 2015

(TACK)"Filarchaeota" Cavalier-Smith, T. 2014[3]

"Aigarchaeota" Nunoura et al. 2011

"Bathyarchaeota" Meng et al. 2014

Crenarchaeota Garrity & Holt 2002

"Geoarchaeota" Kozubal et al. 2013

"Korarchaeota" Barns et al. 1996

Thaumarchaeota Brochier-Armanet et al. 2008

"Asgardarchaeota" Violette Da Cunha et al., 2017

"Lokiarchaeota" Spang et al. 2015

"Thorarchaeota" Seitz et al. 2016

"Odinarchaeota" Katarzyna Zaremba-Niedzwiedzka et al. 2017

"Heimdallarchaeota" Katarzyna Zaremba-Niedzwiedzka et al. 2017

Synonyms

Archaebacteria Woese & Fox, 1977

Mendosicutes Gibbons & Murray, 1978

Metabacteria Hori and Osawa 1979

Archaeal cells have unique properties separating them from the other two domains of Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in the laboratory and have only been detected by analysis of their nucleic acids in samples from their environment.

Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat and square cells of Haloquadratum walsbyi.[7] Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved in transcription and translation. Other aspects of archaeal biochemistry are unique, such as their reliance on ether lipids in their cell membranes, including archaeols. Archaea use more energy sources than eukaryotes: these range from organic compounds, such as sugars, to ammonia, metal ions or even hydrogen gas. Salt-tolerant archaea (the Haloarchaea) use sunlight as an energy source, and other species of archaea fix carbon, but unlike plants and cyanobacteria, no known species of archaea does both. Archaea reproduce asexually by binary fission, fragmentation, or budding; unlike bacteria, no known species of Archaea forms endospores.

The first observed archaea were extremophiles, living in harsh environments, such as hot springs and salt lakes with no other organisms, but improved detection tools led to the discovery of archaea in almost every habitat, including soil, oceans, and marshlands. They are also part of the microbiota of all organisms, and in the human microbiota they are important in the gut, mouth, and on the skin.[8] Archaea are particularly numerous in the oceans, and the archaea in plankton may be one of the most abundant groups of organisms on the planet. Archaea are a major part of Earth's life, and may play roles in the carbon cycle and the nitrogen cycle. No clear examples of archaeal pathogens or parasites are known. Instead they are often mutualists or commensals, such as the methanogens (methane-producing strains) that inhabit the gastrointestinal tract in humans and ruminants, where their vast numbers aid digestion. Methanogens are also used in biogas production and sewage treatment, and biotechnology exploits enzymes from extremophile archaea that can endure high temperatures and organic solvents.

Classification

Origin and evolution

Morphology

Structure, composition development, and operation

Metabolism

Genetics

Reproduction

Ecology

Significance in technology and industry

See also

References

Further reading

External links

Last edited 12 hours ago by Iamnotabunny

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