Dictionary > Archaea

Archaea

Archaea are the unicellular prokaryotes that comprise the domain of the same name, Archaea. These microorganisms are typically found inhabiting and thriving in extreme environmental conditions. They include the halophiles (archaea inhabiting extremely salty environments), methanogens (archaea producing methane), and thermophiles (archaea that thrive in scorching environments).

Archaea definition

Halobacterium sp. strain NRC-1, an archaeon species. In this photo, the cells of Halobacterium sp. strain NRC-1 are in a cluster.

Archaea refers to the microorganisms that physically resemble the bacteria but are genetically distinct from the latter.

Etymology

The term archaea (ar-KAY-ə) (singular: archeon) came from Greek arkhaion, arkhaios, meaning “ancient”. Synonyms: archaebacteria. Compare: eubacteria.

Characteristics

Archaea or archaebacteria evolved separately from eubacteria and eukaryotes. They are similar with eubacteria in being prokaryotes and lacking distinct cell nucleus. They differ in terms of ribosomal structure, the possession of introns (in some species) and in membrane structure or composition. They are similar to eukaryotes in ways that archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes: notably the enzymes involved in transcription and translation.(1)
They are regarded to be living fossils and survivors of an ancient group of organisms that bridged the gap in evolution between eubacteria and eukaryotes.

See also

References

  1. Pace, N. R. (May 2006). “Time for a change”. Nature. 441 (7091): 289. doi:10.1038/441289a

© Biology Online. Content provided and moderated by Biology Online Editors



You will also like...

New Zealand Flora & Fauna
Ecology & Biodiversity: New Zealand Flora & Fauna

New Zealand is known for its unique biodiversity, caused by its remarkable geography and geologic history. Breaking away..

Golgi apparatus (3-D illustration)
Role of Golgi Apparatus & Endoplasmic Reticulum in Protein Synthesis

The endoplasmic reticulum and Golgi apparatus are the organelles involved in the translation step of protein synthesis a..

bryophyte - sporophyte and gametophyte
Meiosis and Alternation of Generations

Plants are characterized by having alternation of generations in their life cycles. This tutorial is a review of plant m..

Genetic engineering
Genetic Engineering Advantages & Disadvantages

This tutorial presents the benefits and the possible adverse eventualities of genetic engineering. Know more about this ..

Young plant growing from the soil.
Soils

Nutrients in the soil are essential to the proper growth of a land plant. This tutorial deals with the properties of soi..

Salmon jumping upstream in the river
Lotic Communities & Animals

A running water environment offers numerous microhabitats for many types of animals. Similar to plants, animals in lotic..