Bacterial Envelope Comparisons


Gram Positive Bacteria:

·        Thick peptidoglycan layer (NAG-NAMA) [90% of cell wall]

·        Connected by amino acid bridges (Alanine, Glutamic Acid)

·        Teichoic throughout peptidoglycan, acts as an antigen

·        Lipoteichoic acid throughout peptidoglycan

·        Gram stain Purple


Gram Negative Bacteria

·        Thin peptidoglycan layer (NAG-NAMA) [20% of cell wall]

·        Periplasmic space

·        Lipopolysaccharide (LPS) =  O side chain + core polysaccharide + Lipid A and Porins

* Gram Stain Red


Acid Fast Bacteria

·        Thin peptidoglycan layer

·        Large amounts of Glycolipids