Lecture 5 Flashcards
(59 cards)
glycol tetrapeptide
structure of repeating unit in peptidoglycan found in coli and most gram neg. bacteria
glycol tetrapeptide repeating units
N-acetylglucosamine and N-acetylmuramic acid
glycosidic bonds
X direction
peptide bonds
Y direction
Gram pos. cells walls can contain up to ___%peptidoglycan
90%
Gram pos. cell walls are common to have ____________ embedded in their walls.
teichoic acids
lipoteichoic acids
teichoic acids covalently bound to membrane lipids
Examples of prokaryotes that lack cell walls?
- mycoplasmas
- thermoplasmas
mycoplasmas
group of pathogenic bacteria
thermoplasma
species of archaea
Gram geg. bacteria walls contain ___% peptidoglycan.
10
Most of the cell wall of gram neg. bacteria walls are composed of…
lipopolysaccharide (LPS) layer
LPS consists of…
core polysaccharide and O-polysaccharide
LPS replaces most phospholipids in the….
outer half of outer membrane
endotoxin
the toxic components of LPS
Lipid A
releases endotoxin when gram neg. cells are lysed
periplasm
gel like consistency space located between cytoplasmic and outer membranes that houses many proteins
How wide is the periplasm
~15nm
porins
channels for movement of hydrophilic low-molecular-weight substances
Archaea has no…
peptidoglycan and outer membrane
pseudomurein
- polysaccharide similar to peptidoglycan composed of N-acetylglucosamine and N-acetylalosaminuronic acid
- found in cell walls of certain methanogenic archaea
T/F all archaea cell walls contain pseudomurein
some cell walls lack pseudomurein
S layers
- present outside other layers of the cell wall
- not in all species
- made of protein
Archaea and the S layer
In some archaea, the S layer is the only cell wall
