Pyruvate Oxidation - Video Tutorials & Practice Problems
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Pyruvate Oxidation
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Video transcript
In this video, we're going to begin our introduction to pyruvate oxidation. And so 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. And these 2 pyruvate molecules that are produced during glycolysis are then transported to the mitochondrial matrix. And in the mitochondrial matrix this is where the second stage of cellular respiration will occur. And so pyruvate oxidation is the second step of cellular respiration. And so pyruvate oxidation is going to convert each of the pyruvate molecules And so And so once again, pyruvate oxidation is going to occur in the mitochondrial matrix. And 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 co a molecules, 2 NADH molecules, and 2 c o 2 or carbon dioxide molecules just from 1 glucose that originally enters the cell. And so what we can see down below in our image here is that we're showing you the 4 stages of aerobic cellular respiration. And in our previous lesson video, we already covered glycolysis, so we can go ahead and give this a check. And glycolysis, again, recall results in the production of 2 pyruvate molecules which end up getting transported mitochondria, and of the mitochondria, and the mitochondria is in the background right here. And so, down below what we can see is another image showing a little bit more details of pyruvate implies with 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. And when pyruvate loses electrons, what ends up gaining the electrons are these NAD plus, which become NADH when they gain the electrons. And so pyruvate oxidation ends up producing 2 NADH. And also notice that each of these black circles in the pyruvates represent carbon atoms, and so each pyruvate has 3 carbon atoms. But notice that one of the carbon atoms from each of the pyruvates is going to get lost as a CO 2 molecule, and so 2 CO2 molecules get produced and these 2 CO2, carbons, get converted into CO2. And the other, carbons of the pyruvate end up getting attached to these, CoA molecules, And so, you can see one molecule of Acetyl CoA here and the second molecule of Acetyl CoA here. And so ultimately, what you can see is that pyruvate oxidation ends up producing 2 NADH, 2 CO twos, and 2 acetyl co a's. And so 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 c o twos, and 2 acetyl coase. And so really this here concludes our introduction to pyruvate oxidation, and you can see that these 2 acetyl Coase, that are produced are going to make their way to the 3rd 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.
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Problem
Problem
Each of the following describes the pyruvate oxidation reaction except that _____________________.
a) It connects glycolysis to the citric acid cycle.
b) Each pyruvate is converted to an acetyl-CoA molecule.
c) NAD+ is reduced to NADH.
d) This reaction occurs within the cytoplasm.
e) Carbon dioxide is released as a by-product.
A
It connects glycolysis to the citric acid cycle.
B
Each pyruvate is converted to an acetyl-CoA molecule.
C
NAD+ is reduced to NADH.
D
This reaction occurs within the cytoplasm.
E
Carbon dioxide is released as a by-product.
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Problem
Problem
In aerobic cellular respiration, pyruvate molecules must be transformed through a process called pyruvate oxidation before they can be broken down in the Krebs Cycle. What are the products of pyruvate oxidation?