Here in this example question, it says, calculate the total ATP yield from the complete beta oxidation of myristic acid. Here, this represents a 14 Carbon Atom Fatty Acid. So here, the way we start is we're going to say step 1, we have to calculate the number of cycles of beta oxidation. Now remember, your number of cycles is number of carbons of the fatty acid divided by 2, minus 1. So, here we have a 14 carbon fatty acid divided by 2 minus 1, so that'd be 7 minus 1, so we'd have 6 cycles.
Next, we're going to calculate the total number of NADH and FADH2 produced during beta oxidation. This is equal to the number of cycles. Because we have 6 cycles that means we're going to have 6 NADH's and 6 FADH2s.
Next, we have to calculate the total ATP, NADH, and FADH2 produced during the Citric Acid Cycle. Now, here this depends on the number of Acetyl CoA molecules from beta oxidation. Remember the number of Acetyl CoA is equal to the number of carbons of your fatty acid divided by 2. So, it'll be 14 divided by 2, so that means we'd have 7 Acetyl CoAs. So, here, we have 7 Acetyl CoAs. We would say that would be 7 times 1 for 7 ATP. We'd have 7 times 3 which gives me 21 NADH's. And then, we would say here, 7 times 1, which would give me 7 FADH2s. Remember, this number of 3 and 1 for NADH and FADH2, we talked about that in the very beginning when it came to the amount of total energy evolved from a fatty acid oxidation. If you don't see that, go back to the previous video to see those values.
Now, here we have to convert our total number of NADH and FADH2 to ATP from Oxidative Phosphorylation. Now remember, 1 NADH is equal to 2.5 ATP. 1 FADH2 is equal to 1.5 ATP. So based on our numbers here, what are we going to do? We're going to say here that we got, 21 NADH's here from the citric acid cycle. And then, also remember we have another 6 NADH's here based on the number of cycles when it comes to beta oxidation. So we'd have 6 + 21 which gives me 27 NADH's. We multiply that by 2.5 ATP which would give me 67.5 ATP total based on NADH. Now, here we have 7 FADH2's from the Citric Acid Cycle and then another 6 that we got from Beta Oxidation based on the number of cycles. So that'd be 6 plus the 7, so that'd give me 13 FADH2. Remember each one is 1.5 ATP, so that give me 19.5 ATP.
Then we're going to say, add all the ATP's and remember there is a one-time expense of 2 ATP involved. So here we'd add up the 67.5 ATP plus the 19.5 ATP minus the one-time cost of 2 ATP, that would give me 85 ATP total. So 85 would be the total amount of our ATP yield when we're talking about the complete beta oxidation of this 14 Carbon Atom Fatty Acid.
