So let's begin with diagram number one. So this is our inner mitochondrial membrane. This is the matrix, and this is the intermembrane space. Now, we generate cytochrome C molecules in their reduced form along complex three. And then the cytochrome C in its reduced form, dissociates from complex three and travels and binds onto complex four. And once it binds onto complex four, it transfers an electron initially to the copper A, copper A center.