Lipid bilayer surrounding the cell wall of Gram-negative bacteria.
The of the outer membrane is where the lipopolysaccharide () resides. Contrast with inner membrane.
A homologous and equivalently named structure is also found in both mitochondria and chloroplasts. In those endosymbiotic organelles the outer membrane surrounds the intermembrane space whereas in Gram-negative bacteria the outer membrane instead surrounds the otherwise intermembrane-space-homologous periplasm.
In general, Gram-negative bacteria have an [outer membrane] separated from the inner membrane by a . This arrangement allows cells to and the environment, as well as export virulence factors to the exterior . Among the structural components, the [outer membrane] is very important in bacterial physiology. In Gram- negative bacteria, the [outer membrane] acts as a strong physical and that protects bacteria from such as , digestive enzymes, and , in addition to many antibiotics .