Calculate the number of ATP molecules obtained in the β-oxidation of myristic acid, CH3(CH2)12 C

Calculate the number of ATP molecules obtained in the...

Key Concepts

Beta?Oxidation Process

Beta?oxidation is the metabolic pathway through which fatty acids are broken down in the mitochondria to produce acetyl?CoA, NADH, and FADH2. In each cycle of beta?oxidation, a two?carbon unit is cleaved from the fatty acid chain, resulting in one molecule of acetyl?CoA while generating reducing equivalents that feed into the electron transport chain for ATP production.

Acetyl?CoA and the Citric Acid Cycle

Acetyl?CoA produced from beta?oxidation enters the citric acid cycle (Krebs cycle), where it is oxidized to generate additional NADH, FADH2, and a small amount of ATP (or GTP). This process further amplifies the ATP yield from the original fatty acid through the electron transport chain, making acetyl?CoA a central molecule in cellular energy metabolism.

ATP Yield Calculation

Calculating the total ATP yield from fatty acid oxidation involves summing the ATP produced directly by substrate-level phosphorylation as well as the ATP generated indirectly from the oxidation of NADH and FADH2 in the electron transport chain. This calculation must also account for any energy cost, such as the ATP used during the activation of the fatty acid prior to beta?oxidation.

Fatty Acid Activation

Before beta?oxidation can occur, fatty acids must be activated by conversion to acyl?CoA, a reaction that consumes ATP (equivalent to 2 ATP molecules). This activation step is crucial as it primes the fatty acid for entry into the mitochondrial beta?oxidation pathway.

Transcript

00:01 So we do have a discrepancy here in the answer in the back of your book.

00:10 It says the answer will be 112 atps produced in the beta oxidation and conversion of all 14 carbons in a 14 carbon fatty acid to co2.

00:27 That is to say with the electron transport and oxygen.

00:31 Oxidative phosphorylation.

00:33 So here's the thing.

00:36 A 14 carbon fatty acid is going to undergo six rounds of beta oxidation.

00:41 Remember that the last round produces two acoas.

00:45 So the number of rounds is always going to be the number of carbons minus two, 14 minus two is 12 divided by two.

00:54 So you get six fadh2s and six nadhs and seven acoas.

01:00 And then those seven acoas will go through the citric acid cycle seven times.

01:06 Well, according to the table that is recommended, you get 10 atp's per turn of the citric acid cycle.

01:15 Again, taking the fadh2 and the nadh produced in the citric acid cycle, taking them through electron transport and oxidative phosphorylation.

01:29 Then those seven eight oas will get you 70 atps, accounting one and a half for each fadh2 as table, what is that table 272, i believe it is, you'll see it gives you a one and a half atp's per fadh2 and two and two and a half per nadh2, so that's going to be the 70 from the citric acid cycle, et, and o .p.

02:08 9 and 15 from the beta oxidation...

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