Oxidative phosphorylation is one of the metabolic stages of cellular respiration . It happens only in the presence of oxygen (aerobic beings), which is necessary to oxidize intermediate molecules and participate in reactions to form the ATP molecule and produce energy .
What is Oxidative Phosphorylation?
In the first stages of cellular respiration (glycolysis and Krebs cycle), part of the energy produced in the degradation of compounds is stored in intermediate molecules, the coenzymes, such as NAD + and FAD +.
This coenzyme oxidation energy is used for the synthesis of ATP . For this, phosphorylation of ADP occurs , that is, it receives phosphate groups. That is why this process is called oxidative phosphorylation.
It is very important, however, that the coenzymes are reoxidized, so that they can participate again in the nutrient degradation cycles, donating more energy for the synthesis of ATP.
The oxidative phosphorylation process happens only in aerobic beings, in which oxygen reoxidates coenzymes through an electron transport chain or respiratory chain , as it is also called.
Electron Conveyor Chain
Many chemical reactions that produce energy release it in the form of heat, which would not be an appropriate mechanism for cells.
To solve this situation, the cellular strategy is to form a proton gradient and produce an energy “carrier” molecule called ATP. This synthesis is mediated by an enzyme complex called ATP synthase.
The protonic gradient is formed through the electron transport chain , which are molecules that are inserted in the mitochondrial membrane, in addition to two mobile components (coenzyme Q and cytochrome c). These molecules are organized according to their redox potential .
Therefore, energy is gradually released through these molecules that are part of the respiratory chain and only at the end of it does hydrogen join with oxygen forming water.
The energy balance of this stage, that is, what is produced throughout the electron transport chain is 38 ATPs.