Archaeal Cell Structure Flashcards
archaea were thought to be _____ but that ______ true
thought to be extremophiles
- but that is not true as not all live in extreme conditions
methanogens
generate methane in anoxic enviro’s
sulfur reducers
generate H2S in sulfur rich enviro’s
extreme halophiles vs thermophiles
halophiles - like very high salt concentrations
thermophiles - like very hot enviros
thermoplasma
wall-less archaea that like hot and acidic enviros (hydrothermal vents)
archaea are most often in what form and they can be _____
bacillal/ coccal forms
they can be pleiomorphic
how do membranes differ in archaea vs bacteria/euk
archaea:
- they have ETHER bonds instead of ester
- derived from isoprenes not FAs
- these bonds make them more stable/ resistant to cleavage
- bonds are branched hydrocarbon chains
do archaea have hopanoids/cholesterol?
NO
the branched chains fill in the gaps
what makes up an ether bond vs ester bond
ether (archaea)
glycerol & phosphate & 2 branched isoprene HC chains
ester (bacteria/euk)
glycerol & phosphate & 2 unbranched FA hydrocarbon chains
compare isoprene glycerol diether, tetraether and pentacyclic rings
glycerol diether - produce lipid bilayer (most fluid)
glycerol tetraether - produce lipid monolayers (less fluid)
pentacylic rings - least fluid
why would it benefit archaea to have stable membranes (not as fluid)
makes them stable in high temps!
archaeal cell walls contain anything but ______ instead they contain ____
anything but peptidoglycan instead they contain pseudomurein
what is the most common cell envelope (external layer) for an archaea
a protein based S-layer
how is pseudomurein different than peptidoglycan (3)
- different sugar (NAT&NAG) not NAM/NAG
- different sugar linkage (B1-3)
- different AA peptide crosslinks (different transpeptidase enzyme)
is gram staining hard to wash out of a thick pseudomurein layer
yes
would lysozyme affect pseudomurein?
no as it has a different linkage B1-3
would penicillin affect pseudomurein?
no as they have a different transpeptidase enzyme and would not be recognized
are antibiotics for archaea?
NO bacteria only !
archaeal cytoplasm
very similar to bacteria / use cytoskeleton homologue proteins
archaeal nucleoid
circular genome
- have histones! which are related to euk and most bacteria do not have
archaea ribosomes
similar to bacteria as also 70s
in relation to flagella bacteria have ____ while archaea have _____
bacteria - flagellin
archaea - archaellin
(in archaella)
full names of NAG/NAM
NAG= N-acetylglucosamine
NAM= N-acetylmuramic acid
