like a stiff “canvas sack” around the bacterial cell.
maintains cell structure.
is a permeability barrier to large molecules (like lysozyme) and hydrophobic molecules; also provides protection from adverse environments like the GI tract.
has an asymmetric bilayer structure: inner leaflet similar to other phospholipid membranes, but outer leaflet contains LPS.
contains a group of transmembrane proteins, porins, that form pores allowing diffusion of small hydrophilic molecules.
is involved in signal transduction, e.g. quorum sensing: communication among bacteria.