PLS HELP 50 points joining ADP molecules and phosphate groups (P). O B. It is the enzyme in an inner membrane that makes ATP by joining ADP molecules and phosphate groups (P), O C. It is the part of the electron transport chain that makes ADP molecules from ATP molecules and phosphate groups (P), D. It is the part of the Krebs cycle that makes ATP by joining ADP molecules and phosphate groups (P)