So let's imagine that our NADH is produced in the citric acid cycle and then that NADH travels to protein complex number one and it gives the two electrons to protein complex number one. Now, when it donates those two electrons, those two electrons go onto a molecule known as Flavin mononucleotide, or FMN. So we reduce FMM, which is basically a group that is found on protein complex number one. And then those electrons basically travel via a series of groups, our iron sulfur groups, and eventually end up on a molecule known as Ubiquinon, shown by this Q circular symbol. So this is Ubiquinon, and Ubiquinon is basically an important electron carrier. So Ubiquinon is soluble inside our phospholipid bilayer membrane, and it can basically move along our membrane.