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The cell wall is composed of pseudopeptidoglycan (and not peptidoglycan as in bacteria) which makes archaea resistant to lysozyme and many antibiotics that interfere with cell wall synthesis. The cell membrane consists of a lipid bilayer or monolayer, the backbone of which is composed of isoprene units that are linked to glycerol by ether bonds.
The cell membrane of archaea consist mostly of ether phospholipids. These lipids have a flipped chirality compared to bacterial and eukaryotic membranes, a conundrum known as the " lipid divide ". The "tail" groups are also not simply n-alkyl groups, but highly methylated chains made up of saturated isoprenoid units (e.g. phytanyl ).
Archaea were initially classified as bacteria, receiving the name archaebacteria (/ ˌ ɑːr k i b æ k ˈ t ɪər i ə /, in the Archaebacteria kingdom), but this term has fallen out of use. [5] Archaeal cells have unique properties separating them from Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla.
The cell envelope is composed of the cell membrane and the cell wall. As in other organisms, the bacterial cell wall provides structural integrity to the cell. In prokaryotes , the primary function of the cell wall is to protect the cell from internal turgor pressure caused by the much higher concentrations of proteins and other molecules ...
This causes the membrane to be composed of monolayers with polar groups at each end. The cells are rod-shaped with diameters of up to 4 micrometres and up to 100 micrometres in length, and reproduce by developing branches on the end of the cell which grow into individual cells. They are motile by flagella.
Methanobacteriati (from Ancient Greek εὐρύς eurús, "broad, wide") is a kingdom of archaea. [3] Methanobacteriati are highly diverse and include methanogens, which produce methane and are often found in intestines; halobacteria, which survive extreme concentrations of salt; and some extremely thermophilic aerobes and anaerobes, which generally live at temperatures between 41 and 122 °C.
An S-layer (surface layer) is a part of the cell envelope found in almost all archaea, as well as in many types of bacteria. [1] [2] The S-layers of both archaea and bacteria consists of a monomolecular layer composed of only one (or, in a few cases, two) identical proteins or glycoproteins. [3]
In most organisms, the cell membrane consists of a lipid bilayer in which phospholipids arrange with their hydrophobic, nonpolar hydrocarbon tails facing inwards towards one another and their hydrophilic, polar head groups facing outwards to associate with the polar environments of the cytoplasm or cell exterior.