And finally we have this delta chain as shown right over here. Now the delta subunit basically helps hold this entire hexameric structure in place so that it doesn't actually rotate. It is also actually used to connect this hexameric structure to this structure here that is part of the F not unit. So now let's move on and discuss the F zero unit. Now the F one region basically contains the catalytic unit while the F zero region as we'll see in just a moment actually contains that structure that allows the movement of the protons, the hydrogen ions down their electrochemical gradient from the intermembrane side to the matrix side of our ATP synthase. So the F knot region is mostly hydrophobic and lies within the inner membrane of the mitochondria and basically consists of two types of units.