BACTERIAL MORPHOLOGY CONTD...
4) Cell wall: It is a rigid structure that lies beneath external structures( Pili, capsule, flagella) & external to cytoplasmic membrane. It gives shape & rigidity to cell. Cell wall consists network of peptidoglycan layer( murein or mucopeptide).
In Gram Negative, the cross-linkage occurs by peptide linkage of amino group of DAP to carboxyl group of D-alanine. Eg. E.coli peptidoglycan with direct cross linkage, a typical gram negative bacteria.
Fig: Peptidoglycan Composition