Growing point of Peptidoglycan cell wall Cytoplasmic Pentapeptide membrane Bactoprenol a G -Ala-D-Glu-DAP-D-Ala-D-Ala Transpeptidation DAP—D-GIu-L-Ala D-Ala L-Ala-D-Glu-DAP-D-Ala-DAP-D-Glu-L-Ala D-Ala (b)