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 proteinsthat form pores for hydrophilic molecule diffusion and Lipopolysaccharideswith a negative charge that helps maintain bacteria's shape, but also potentially causes toxic shock in infected hosts.