Archaea

Archaea
A unique group of microorganisms classified as bacteria (Archaeobacteria) but genetically and metabolically different from all other known bacteria. They appear to be living fossils, the survivors of an ancient group of organisms that bridged the gap in evolution between bacteria and the eukaryotes (multicellular organisms). The name Archaea comes from the Greek archaios meaning ancient.

* * *

Ar·chaea (ahr-keґə) [Gr. archaios ancient, from archē beginning, from archein to begin] in the three-domain system of classfication, one of the two large divisions into which prokaryotes are grouped, genetically distinct from bacteria and sharing some molecular features with the eukaryotes. Organisms are diverse in shape and size, may or may not have a cell wall, and occur both as unicellular forms and as filaments or aggregations. They are subclassfied into methanogenic, sulfate-reducing, halophilic, and thermophilic groups. Members are predominantly terrestrial or aquatic organisms, living mainly in extreme environments, such as submarine hydrothermal vents and subterranean salt deposits; some occur as symbionts in the digestive tracts of animals. None are human pathogens. Cf. Bacteria.

Medical dictionary. 2011.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Archaea — Saltar a navegación, búsqueda ? Archaea Rango fósil: Arcaico Holoceno Halobacteria sp. cepa NRC 1, cada …   Wikipedia Español

  • archaea — [är kē′ə] pl.n. ARCHAEBACTERIA archaeal adj. * * * ▪ bacteria formerly  archaebacteria         unicellular organisms that are prokaryotic (that is, do not have a membrane bound nucleus and other internal units) but that differ in cert …   Universalium

  • Archaea — Archaea, Archaeen, Überreich der Organismen, dem die ⇒ Archaebacteria zugeordnet werden …   Deutsch wörterbuch der biologie

  • ARCHAEA — Aeolidis in Asia urbs. Pausan. l. 2 …   Hofmann J. Lexicon universale

  • archaea — [är kē′ə] pl.n. ARCHAEBACTERIA archaeal adj …   English World dictionary

  • Archaea — см …   Генетика. Энциклопедический словарь

  • Archaea — Archea redirects here. For the geologic eon, see Archean. For the spider family, see Archaeidae. Archaea Temporal range: Paleoarchean – Recent Halobacteria sp. strain NRC 1, each cell about 5 μm long …   Wikipedia

  • Archaea — Archées …   Wikipédia en Français

  • Archaea — Archaeen Archaeon des Genus Sulfolobus, infiziert mit dem Sulfolobus Virus STSV1. Maßstab = 1 μm. Systematik Klassifikation …   Deutsch Wikipedia

  • archaea — noun plural Etymology: New Latin, from Greek archaios Date: 1990 microorganisms of a domain (Archaea) including especially methane producing forms, some red halophilic forms, and others of harsh hot acidic environments (as a hot spring) compare… …   New Collegiate Dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”