When it gains a single electron, it is reduced into the Fe two plus form. So remember, in the Hen group, we have the iron atom that can actually gain that electron. And when gains that electron, it is reduced. And so as the electron travels from the risky sensor to the Cytochrome C one, it actually attaches onto the iron atom of the Heme group, and so it is reduced. Now, the electron travels from the Hen group and ultimately ends up on the Heme group of Cytochrome C. And notice, only a single electron can actually bind onto Cytochrome C. So this is the major difference between Cytochrome C electron carrier and the Ubiquinone electron carrier. Ubiquinone is able to actually bind two electrons, but Cytochrome C can only bind a single electron.