Question

List four chemical and/or structural differences that distinguish gram-positive from gram-negative bacteria.

a.

b.

c.

d.

Answer 1

Difference between gram positive and gram negative bacteria

Characteristic features	Gram-positive bacteria	Gram-negative bacteria
a) Cell wall	Cell wall is thick (20-30 nm)	Cell wall is thick (8-12 nm)
b) Peptidoglycan	Peptidoglycan layer is thick	Peptidoglycan layer is thin
Tc) eichoic acid	Present	Absent
d) Lipopolysaccharide	Absent	Present
e) Lipid and lipoprotein content	Low	high
f) Outer membrane	Absent	present
g) Periplasmic space	Absent	Present