Nadh yield how many atp

In eukaryotic cells, unlike prokaryotes, NADH generated in the cytoplasm during glycolysis must be transported across the mitochondrial membrane before it can transfer electrons to the electron transport chain and this requires energy. For simplicity, however, we will look at the theoretical maximum yield of ATP per glucose molecule oxidized by aerobic respiration.

Keep in mind, however, that less ATP may actually be generated. Chapter Cell Cycle and Division. Chapter Meiosis. Chapter Classical and Modern Genetics.

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Full Table of Contents. This is a sample clip. Sign in or start your free trial. JoVE Core Biology. And along the inner mitochondrial membrane, we have a series of proteins that are known as protein complexes. And you know, these all have specific names, but just for our purposes, it's important to recognize there are kind of just four main protein complexes, and in some textbooks, people will actually call ATP synthase, which I'm gonna go ahead and draw here in yellow as complex number five, so let me go ahead and label these, one through five, just so we remember that, so, these four represent the protein complexes that shuttle electrons and of course, five represents ATP synthase.

Now, recall that the basic premise here is that these reduced electron carriers donate electrons to the electron transport chain and in fact, specifically, NADH donates two electrons to protein complex number one, and FADH two donates two electrons to protein complex number two. Now, the second important point is that as these electrons are kind of flowing down these proteins, for every two electrons that kind of flow by, it's actually been calculated that protein complex number one pumps four protons into the intermembrane space, protein complex three, it pumps, also, four protons, and protein complex number four pumps two protons.

And protein complex number two doesn't really contribute. Now, with these facts in mind, we can go ahead and actually calculate how many protons are pumped for a molecule of FADH two and how many protons are pumped for a molecule of NADH. So, let's go ahead and just quickly do that here, so because NADH donates at the very first electron complex, it contributes to a total of four plus four plus two, or ten protons are pumped out for every molecule of NADH.

On the other hand, FADH two enters in complex number two, so it only contributes to the total pumping of six protons and so, we can say that there are six protons that are pumped for every molecule of FADH two. And so, of course, maybe the question we should really be asking is how many protons does it take, or how many protons need to flow through this ATP synthase to phosphorylate one molecule of ADP into ATP, and so, I'm actually gonna go ahead back to our ratios up here and write up here that if we knew how many protons were necessary to produce one molecule of ATP, we would be able to calculate essentially the ratio of ATP to NADH or FADH two.

And it's this calculation that I think researchers are actually still trying to, you know, nail down and, you know, I'm sure depending on the type of cell and the state of the cells, the efficiency of this process is going to be different and might, you know, change moment to moment and so, maybe the expectation to have an exact number is not realistic, but researchers are pretty confident with the number, right now, currently of four protons being necessary to produce one molecule of ATP, so, I'm gonna go ahead and just write that in here.

So, remember, that even though it's kind of funky that we're talking about kind of two and a half ATP per molecule of NADH or per molecule of FADH two, really, what this is alluding to is the role of this chemi-osmotic coupling, or using the proton gradient to fuel to ATP synthase and because we're talking about protons now, we need to factor in that, we end up getting these non whole number ratios between ATP and NADH or FADH two.

But with these ratios in mind, I actually wanna go ahead and calculate kinda the sum total of ATP that we produce in cellular respiration, so I've already gone ahead and kinda created a table here, and remember that we're talking about one cycle of cellular respiration, so, as a total ATP yield, let's say per one molecule of glucose, remember.

And six NADH times two point five is going to yield And two FADH two times one point five is going to yield three. And so, if we add all of this up, we get 32 ATP. Now, before I call it good, I wanna make one more last nitpicky point which is to realize that glycolysis, remember, takes place in the cytosol, so unlike the oxidation of pyruvate and the Krebs cycle, which take place in the mitochondria, the NADH that's produced in the glycolysis must actually be shuttled somehow into the inner mitochondrial membrane in order to donate its electrons into the electron transport chain.

But for some reason, it turns out that the inner mitochondrial membrane is actually not permeable to this molecule NADH.