Oxygen
Oxygen is the most abundant element in the Earth. All molecules in the living body that make up cells, such as fats, carbohydrates and proteins contain oxygen. During the respiration processes in living cells, oxygen is the final hydrogen acceptor, which means it is the last molecule or co-enzyme of the electron transmitter chain that releases an electron. The electron is transmitted to a cell and used to synthesize or create adenosine triphosphate, commonly called ATP. ATP is the molecule that gives energy to cells in the body.
Oxidative Phosphorylation
Oxidative phosphorylation is the name of the metabolic process or pathway that uses the energy released when nutrients consumed by a living biological organism are oxidized to create ATP. During this process, electrons move from electron donors -- nutrient molecules -- to electron acceptors -- oxygen molecules.
Oxygen's Role
Oxygen enables the oxidation of food once it is broken down into molecules by the digestive system of the organism. The oxidation of the molecules in the cells of the organism allows it to store energy as ATP and promote the process of chemiosmosis. If this reaction were an electrical circuit, the nutrients act as the light switch, the oxygen acts as a conductive wire or a transmitter of the electricity and allows the energy to flow from its source, and the ATP is the electricity that turns on the light.
Chemiosmosis
Oxygen is used to promote the process of chemiosmosis. Chemiosmosis occurs when the energy is transferred from the electron transport chain to ATP via the movement of protons across a cell membrane. Chemiosmosis is an important process in cellular metabolism. Osmosis is when water molecules pass a permeable membrane in a cell. Chemiosmosis is when positively charged hydrogen ions called protons move across a selective permeable membrane of a cell. This causes the protons to diffuse across the membrane and concentrate into a form of energy. The proton gradient created during this process provides the energy for the creation or synthesis of ATP.