The cell walls of Gram positive bacteria contain two modified sugar, viz. N- acetylgucosamine (NAG) and N- acetylmuramic acid (NAM). They are covalently linked by

• α- 1,4-glycosidic bond
• β-1,6-glycosidic bond
• α- 1,6-glycosidic bond
• β- 1,4-glycosidic bond