So at the same time that the ATP moves out of the matrix into the cytoplasm, the ADP is brought from the cytoplasm and into the matrix so that oxidative asphorylation of the ADP can take place along the electron transport chain found on the inner membrane of the mitochondria. Now, before we actually take a look at the mechanism by which ATP ADP translocase actually functions, let's discuss what the structure of ATP ADP translocase actually is. Well, this is a homodymer molecule and what that means is it consists of two identical polypeptide chains and each one of these identical polypeptide chains consist of six alpha helices that span the membrane. And these two identical polypeptide subunits basically work together to create this conformation in which we have a binding pocket that can bind ATP and ATP. And this binding pocket actually alternates between facing the matrix side and facing the cytoplasmic side, as we'll see in just a moment. So because along the inner membrane of the mitochondria, we have the electron transport chain which actually functions to generate these ATP molecules from ADP molecules, we might imagine that the inner mitochondrial membrane contains a relatively high concentration of this specific translocase.