So, let's begin with our succinate. The succinate looks something like this. We have the carbon 1234, and these two H atoms shown in purple will basically react with a single fad molecule. And that fad molecule will be reduced. It will take these two H atoms, as well as a single electron from each one of these atoms, which will end up on this molecule known as our fadh two high energy electron carrier. And once these two leave, we form a pi bond between carbon one and carbon two, as shown.