So once this electron binds onto the oxidized Cytochrome C, it reduces that Cytochrome C the cytochrome C then detaches and diffuses within the fluid of the intermembrane space and travels and binds onto complex four. While the other electron, because it cannot go via this same pathway, it follows a different pathway. And that's where Cytochrome B comes into play. Cytochrome B actually contains two different heme groups. And the electron first moves on to one heme group, then a second Hen group, and then it ultimately ends up on Ubiquinone. So this is basically the fully oxidized version of coal enzyme Q, also known as Ubiquinone.