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Archaea

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Archaea
The domain that contains microbes with isoprenoid glycerol diether or diglycerol tetraether lipids in their membranes and archaeal rRNA (among many other features)
Bacteriorhodopsin
A transmembranous protein to which retinal is bound; it functions as a light-driven proton pump, allowing photophosphorylation without chlorophyll or bacteriochlorophyll; found in the purple membrane of halophilic archaea
Halophile
A microorganism that requires high levels of sodium chloride for growth
Hyperthermophile
A microorganism that grows optimally at temperatures greater than 85 degrees C
Methanogen
Strictly anaerobic archaea that derive energy by converting carbon dioxide, hydrogen gas, formate, acetate, and other compounds to either methane or methane and carbon dioxide
Pseudomurein
A peptidoglycan-like polymer found in some archaeal cell walls; it is distinguished from peptidoglycan by the presence of L-amino acids, N-acetyltalosaminuronic acid (NAT) and beta (1 to 3) glycosidic bonds
Sensory rhodopsin
A form of rhodopsin found in halobacteria and cyanobacteria that senses the spectral quality of light
Thermoacidophiles
Microorganism that grow best at high temperatures and low pH
Euryarchaeota
Occupy many different ecological niches and have a variety of metabolic patterns; includes methanogens, extreme halophiles, sulfate reducers, and many extreme thermophiles with sulfur-dependent metabolism
Crenarchaeol
Cyclopentane ring-containing lipids unique to Crenarchaeota; used as a biomarker for the presence of crenarchaeotes in natural environments such as marine plankton
Selenocysteine
21st amino acid incorporated into two specific regions of archaeal mRNA; synthesized from serine; found in all domains of life
Pyrrolysine
22nd amino acid present only in several methanogenic archaea and a single bacterium; derived from lysine
Pseudomurein, chondroitin sulfate-like polysaccharides, or protein walls
What do archaeal cell walls have instead of peptidoglycan?
Have ether instead of ester linkages, long tetraethers, and pentacyclic rings
How do the membrane lipids of archaea differ from those of other organisms?
Increased core hydrophobicity, packing density, and hydrogen bonds
How are proteins made more rigid in thermophiles?
Increased supercoiling
How is DNA protected from denaturation in thermophiles?
Irregularly lobed, spherical cells
What shape are cells in the genus Sulfolobus?
Thermoacidophiles
What type of "-philes" are members of the genus Sulfolobus?
Long, thin, bent or branched rods
What shape are cells in the genus Thermoproteus?
Glycoprotein
What is the cell wall of members of the genus Thermoproteus composed of?
Hot springs
Where are members of the genus Thermoproteus found?
Halobacteria
Which group(s) of Archaea use bacteriorhodopsin in their purple membrane?
Outward proton transport
What is the function of bacteriorhodopsin?
Inward chloride ion transport
What is the function of halorhodopsin?
Purple membrane
Modified region of the plasma membrane containing bacteriorhodopsin molecules
Proteorhodopsin
Rhodopsin found in α- and β-proteobacteria and the Bacteroidetes