So this Q cycle begins when the Ubiquinol QH two attaches onto complex three, as shown here. And upon binding, the two electrons follow two different pathways, and the two protons are pumped into the intermembrane space of the mitochondria. Now, one of these electrons moves onto the risky center, the two fe two sulfur group of the risky center, and then it is transferred onto the heme group of Cytochrome C one, reducing the three plus form into the two plus form. From there, it is then picked up by the final, except the Cytochrome C. And when Cytochrome C accents that electron, it itself is reduced. And that stimulates the detachment of the Cytochrome C is then is able to move along the fluid of the intermembrane space and attach onto complex four, as we'll see in the next lecture. Now, what about that other electron?