And in this lecture I'd like to focus on the structure of ATP synthase complex five of the electron transport chain. So just like the previous complexes, complex five is also found in the inner membrane of the mitochondria and it has the following elaborate structure. So the structure of ATP synthase is quite complex and we can break down the structure into two general regions. 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.