archaeal diversity Flashcards
how are archaea similar to bacteria
- lack nucleus
- lack membrane bound organelles
- 70s ribosomes
- unicellular most the time
what was the main feature, discovered by Woese et al, which differs between archaea and bacteria
their 16s rRNA nucleotide sequence was very different
who was the common ancestor between bacteria and arachaea
LUCA, but they followed different evolutionary paths
what are some similarities between archaea and eukaryotes
- DNA polyermase and RNA polymerase are similar
- RNAP and RNAPII are simialr
outline the structure of an archaea cell envelope
a glycerol phosphate head attached to two isoprenoids
(any class of organic compound composed of two or more units of hydrocarbons with 5 carbon atoms arranged in a specific pattern)
why can arachaea withstand more extreme conditions than bacteria
the isoprenoid bilayer is more stable than bacterial phospholipid membranes at low PH, high temp and salt conc
what is an S-layer
a glycosylated proteinaceous surface layer
what are arachaeal walls made of
some polysaccharides
some pesudomurein or pesudopeptidoglycan
what makes the cell wall or an archaea lysozyme insensitive
the N-acetylglucosamine and N-acetyltalosaminuric aicds linked by beta 1-3 glycosylic bonds instead od beta 1-4
what do arachaea with no cell wall protetc themselves with
an s-layer consisting of proteins and glycoproteins interlocked forming a lattice
what are the 4 super-pyla that archaea are organised into
1) TACK
2) DPANN
3) euryarcheota
4) asgard
what are thermoacidophiles
a type of archaea which grow at more than 70c and a PH as low as 2
what are halophiles
a type of archaea which need high salt concentrations to grow otherwise they lyse
what is bacteriorhodopsin
a membrane protein which acts as a light driven proton pump which absorbs photons resulting int he trabnsport of protons out the cell creating a gradient which ATPsynthase can use to form ATP
what are methanogens
a type of archaea which use co2 for respiration reducing it to methane
