A bacterial outer membrane is an additional membrane outside the peptidoglycan in typical Gram-negative bacteria. It adds a barrier while the inner cell membrane remains the boundary of the cytoplasm.
The periplasm is the compartment between the cytoplasmic and outer membranes in a typical Gram-negative bacterial envelope. Its components and the outer membrane can gate access of external electron acceptors.
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Only present in Gram-negative bacteria.
Structure of a Gram-negative bacteria
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