We have the f zero region and the f one region. Now the f zero region is this section here and the f one region is this section here. Let's begin by describing the f one region. Now the f one region basically consists of those polypeptide chains which are responsible for actually binding the ADP molecules and the orthophosphate molecules and forming those ATP and releasing the ATP into the matrix of that mitochondria. So the f one region is the catalytic unit of this complex. So this region basically lies in the matrix of the mitochondria.