Because it synthesizes ATP from ADP. About 38 molecules of ATP may be produced from glucose. The presence of oxygen effects the chemical pathways used to extract energy from glucose because oxygen is more efficient in breaking down glucose into co2 and water. This creates much larger amounts of ATP compared to the pathways used when oxygen is absent. Hydrogen ions are important for ATP productions because in the oxidative phosphorylation process, they play a huge role. They are also involved in the electron transport chain, the proton gradient, and ATP synthase. The movement of hydrogen ions across the mitochondrion is essential for the electron gradients that starts ATP synthesis.