Now, the function of this hexameric structure, as we'll see in the future lecture, is to actually bind the ADP and the orthophosphate molecules to synthesize the ATP molecules and then release the ATP molecules into the matrix of the mitochondria. Now, although the alpha units can in fact bind the ATP molecules, only the beta units of this hexamer have the capability of actually synthesizing and releasing those ATP molecules. So once again, the three alpha and the three beta chains combine to form a hexameric alpha three beta three ring structure that will be responsible for catalyzing the synthesis of ATP molecules. And once again, although both of these chains, alpha and beta, have the ability to bind ATP, only the beta has the ability to actually synthesize and release those ATP molecules into the matrix of the mitochondria and we'll discuss how that mechanism actually takes place in a future lecture. Now so we discussed the alpha and the beta units. Now let's move on to the gamma and the epsilon unit.