Gram-negative cell wall
The Gram-negative bacterial cell wall consists of three primary layers:.
1. The cytoplasmic membrane
2. A thin peptidoglycan layer, located in the periplasmic space
3. An outer membrane containing lipopolysaccharides and porin proteins
Figure 1. Upper image. Gram-negative bacterial cell wall. Lower image. Lipopolysaccharide
Cytoplasmic membrane: surrounds bacteria's cytoplasm, controls molecular movement, and is composed of proteins and lipids, similar to mammalian cells.
Peptidoglycan: in Gram-negative cell walls is a thin mesh of repeating subunits containing sugars and amino acids.
The Periplasmic space: lies between the outer and cytoplasmic membranes, containing a gel-like matrix with vital proteins for cell functions.
The outer membrane shields bacteria and hinders some antibiotics. It contains Porin proteins that form pores for hydrophilic molecule diffusion and Lipopolysaccharides with a negative charge that helps maintain bacteria's shape, but also potentially causes toxic shock in infected hosts.