BSC 310 Lecture 7: 2.5-2.7 - The Outer Membrane, Archaeal Cell Walls, Cell Surface Structures
18 Jan 2019
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Document Summary
Only ~10% of gram-negative cell wall consists of peptidoglycan. Most is composed of the outer membrane , a 2nd lipid bilayer outside of the peptidoglycan. This outer membrane also contains polysaccharides that are linked to the lipids (fa tails), resulting in the name lipopolysaccharide layer ( lps ) Does not confer strength nor rigidity, but acts as an additional barrier for movement across the cytoplasmic membrane. The space in between the membranes is the periplasm. Polysaccharide consists of 2 (really 3) components: Lipid a : not a typical glycerol lipid; the fatty acids are connected through the amine groups of a disaccharide. Hydrophobic interior portion of the outer membrane. Braun lipoprotein attaches the outer membrane to the peptidoglycan. Lps is extremely toxic to animals lipid a. Much of the pathogenicity of gram-negative bacteria is due to the toxicity of. Endotoxins are often found in organisms that cause food poisoning.
