In this video, we're going to begin our introduction to pyruvate oxidation. First, we need to recall from our previous lesson videos that the first stage of cellular respiration, or glycolysis, actually results in the production of 2 pyruvate molecules. These 2 pyruvate molecules that are produced during glycolysis are then transported to the mitochondrial matrix. In the mitochondrial matrix, the second stage of cellular respiration will occur. Pyruvate oxidation is the second step of cellular respiration. Pyruvate oxidation is going to convert each of the pyruvate molecules that were produced into a molecule known as Acetyl CoA. Once again, pyruvate oxidation will occur in the mitochondrial matrix. Because pyruvate oxidation is the second step of cellular respiration, it makes it pretty easy to remember that pyruvate oxidation is going to produce 2 Acetyl CoA molecules, 2 NADH molecules, and 2 CO2 (carbon dioxide) molecules just from 1 glucose that originally enters the cell.
What we can see down below in our image here is that we're showing you the 4 stages of aerobic cellular respiration. In our previous lesson video, we already covered glycolysis, so we can go ahead and give this a check. Glycolysis, again, recall results in the production of 2 pyruvate molecules which end up getting transported of the mitochondria, and the mitochondria is in the background right here.
Down below, we can see another image showing a little bit more details of pyruvate oxidation. Pyruvate, which is the molecule that it starts with, is going to end up getting oxidized, which means that pyruvate is going to lose electrons. When pyruvate loses electrons, what ends up gaining the electrons are these NAD+ molecules, which become NADH when they gain the electrons. Pyruvate oxidation ends up producing 2 NADH. Notice that each of these black circles in the pyruvates represent carbon atoms, so each pyruvate has 3 carbon atoms. Notice that one of the carbon atoms from each of the pyruvates is going to get lost as a CO2 molecule, so 2 CO2 molecules get produced and these 2 CO2 carbons get converted into CO2. The other carbons of the pyruvate end up getting attached to these CoA molecules. You can see one molecule of Acetyl CoA here and the second molecule of Acetyl CoA here.
Ultimately, you can see that pyruvate oxidation ends up producing 2 NADH, 2 CO2s, and 2 Acetyl CoA's. It's helpful to know that because pyruvate oxidation is the second step of cellular respiration, the second step, that makes it easy to remember that it produces 2 NADHs, 2 CO2s, and 2 Acetyl CoAs.
This concludes our introduction to pyruvate oxidation, and you can see that these 2 Acetyl CoAs that are produced are going to make their way to the third step of cellular respiration, which is the Krebs cycle, and we'll get to talk about that as we move forward in our course. So I'll see you all in our next video.
