So in step number one, the two carbon acetal group of acetyl, Coenzyme A, is combined with the four carbon oxylacetate to form this six carbon molecule known as the tricarboxylic acid. And that's why sometimes we call it the tricarboxylic acid cycle TCA cycle. Now, in the next two steps, in step two and three, we undergo a decarboxylation reaction, an oxidation reduction reaction. So in step two, the six carbon molecule becomes a five carbon molecule. In the process, we release a CO2 and we also generate, we release, we abstract two electrons from the carbon six molecule. And those two electrons are picked up by the NAD plus molecule to form NADH.