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

The image presents the cross section of a gram-negative cell wall. At the bottom is a cytoplasmic membrane with proteins embedded into it. On top of it, a thin peptidoglycan layer with lipoproteins is placed, followed by outer membrane with porin structures and lipopolysaccharides, extending from the outer membrane towards the external environment.
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.