Mod 2 Lec 4: Bact cell surface structure (Gram -ve) Flashcards
where is lipopolysaccharide
in outer membrane
name the 3 compnents of lipopolysaccharide
o-antigen/o-specific polysaccharide
core oligosaccharide
lipid A - embedded in outer membrane, and conserved
where are porins located
outer memb of bacteria
name of space beterrn outer memb and cytoplasmic memb
periplasmic space
this is where thin peptidoglycan layer is btw
what is lipid A made of
D-glucosamine disaccharide (1,6 linked)
Phosphate groups and 1’ and 4’
3-hydroxy fatty acids
what is core oligosaccharide made of
diff sugars
this varies between bacteria
what does o antigen consist of
variable sugars (variation BETWEEN bacteria, not within the o-antigen bit)
but they’re repeated units
what are TLRs
toll like receptors
part of our immune system that recognise the lipid A part of LPS
what is lipid A also known as
endotoxin
which TLR does endotoxin stimulate
TLR-4
what can endotoxic shock lead to
multi organ failure
are archaea membranes monoderm or diderm and what are they made of (extremeophiles)
monoderm
tetra-ether lipids (isoprenyl groups linked through glycerol backbone via an ether bond)
this makes it impermeable to protons hence why its good for rly acidic conditions
what is s layer
in all archae
paracrystalline layer composed of only one (or, in a few cases, two) identical proteins or glycoproteins
forms protective structure with narrow pores to limit access to cells
mesophilic archae: what is membrane made of
pseudomurein layer
and then underneath is bilayer of diether lipids
wha is pseudomurein
archae equivalent to peptidoglycan
some have it and some dont
