DIFFERENCE BETWEEN GRAM POSITIVE AND GRAM NEGATIVE BACTERIAL CELL WALL

Difference between Gram positive bacterial cell wall and Gram negative bacterial cell wall

Features	Gram Positive Bacterial Cell wall	Gram Negative Bacterial Cell wall
Gram staining	Appears in Violet colour	Appears in Pink colour
Thickness	15 – 18 nm	7 – 8 nm
Peptidoglycan	Thick (Multilayered)	Thin (Single layered)
Teichoic acids	Present	Absent
Periplasmic space	Absent	Present
Outer membrane	Absent	Present
Lipopolysaccharides	Low	High
Lipid & Lipoproteins	Low (Only in Acid fast bacteria have lipid linked to Peptidoglycan)	High (because of the presence of Outer membrane)
Porins	Absent	Present
Cell wall disruption by Lysozymes	High (After digestion of peptidoglycan layer, Gram positive bacteria become Protoplast)	Low (After digestion of peptidoglycan layer, Gram   negative bacteria become Spheroplast)
Rigidity and Elasticity	High rigid & Less elastic	Less rigid & High elastic
NAG	Present	Present
Presence of NAM	Present	Present
Glycosidic linkage	β-1,4 glycosidic linkage	β-1,4 glycosidic linkage
Pseudo-crystalline Proteinaceous Surface Layer (S - layer)	Absent	Absent
Methanochondrotin (cell wall polymer)	Absent	Absent
Protein sheaths	Absent	Absent
Sensitivity to Penicillin	Sensitive	Resistant