Step 1 Glucose enters glycolysis pathway and glycolysis yields pyruvate, then pyruvate undergoes processing. step 2 Pyruvate processing ;releases acetylCOA which joins the citric acid cycle. Step 3 The citric acid cycle yields 2ATP and CO2 and also releases NADH and FADH2 to electron transport chain and chemiosmosis. Step 4 Chemiosmosis and electron transport chain yields 25 ATP molecules and H2O Oxygen enters electron transport chain and osmosis.