What is the difference between gram-positive and gram-negative bacteria?

Gram-positive bacteria: thick, cross-linked cell wall composed of peptidoglycan, only consist of peptidoglycan and cytoplasmic membrane, contain many proteins and acids, stain purple gram-negative bacteria: consist of outer membrane, periplasmic space with some peptidoglycan, cytoplasmic membrane. contain endotoxin, stain red becasue of the thin layer