This is the matrix of the mitochondria and this is the intermembrane space. And this entire structure is the F knot region. And the F knot region lies within the membrane of the mitochondria within the inner membrane. Now, in this particular case, I've drawn ten of these individual C subunits that form this cring. And we have the A subunit that is found in close proximity to this C ring. Now, if we zoom in onto this A subunit this is basically what we're going to see.