Difference between Gram -ve and Gram +ve Bacteria

Bacteria are generally classified into two groups on the basis of Gram staining based on the amount of peptidoglycan present in the cell wall.Though it is found that Gram positive and gram negative bacteria have certain other variable characteristics other than merely the result of Gram staining: Gram positive- 1.They retain the crystal violet stain after gram staining. 2.They have peptidoglycan layer thickness about 20-80nm and about 40-60 layers thick. 3.Peptidoglycan is much more mesh like and has interpeptide cross linkages. 4.cell wall has techoic acids which confer negative charges to the cell wall. 5.Have only one periplasmic space. Gram negative- 1.They retain the colour of safranine,the counter stain of gram stain, and not the colour of the primary stain crystal violet. 2.The cell wall has an additional layer outside the peptidoglycan layer known as the outer membrane. 3.The outer membrane contains lipid-A,core polysaccharide and the O-side chain. 4.Lipid A portion of core polysaccharide is known as endotoxin and help in virulence. 5.O side chain is also known as o specific antigen as it elicits an immune response. 6.Peptidoglycan has a thickness of 2-7 nm . 7.It has two periplasmic spaces on either side of petidoglycan layer.