Number of ATP formed by oxidation of one molecule of palmitic acid (16c):
**Core Concept**
The question tests the understanding of the number of ATP molecules generated during the complete oxidation of a fatty acid, specifically palmitic acid. This process involves the breakdown of fatty acids through beta-oxidation, the citric acid cycle, and oxidative phosphorylation. The number of ATP molecules produced depends on the chain length of the fatty acid and the number of NADH and FADH2 molecules generated.
**Why the Correct Answer is Right**
During the complete oxidation of palmitic acid, 16 carbons are broken down into 8 acetyl-CoA molecules. Each acetyl-CoA enters the citric acid cycle, generating 10 ATP molecules, 6 NADH molecules, and 2 FADH2 molecules. The 6 NADH molecules produce 24 ATP molecules, and the 2 FADH2 molecules produce 4 ATP molecules. Additionally, the citric acid cycle generates 8 ATP molecules directly. Therefore, the total number of ATP molecules produced from the complete oxidation of palmitic acid is 24 + 4 + 8 = 36.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it fails to account for the ATP molecules produced from the citric acid cycle and the electron transport chain.
**Option B:** This option is incorrect because it underestimates the number of ATP molecules produced from the NADH and FADH2 molecules.
**Option C:** This option is incorrect because it fails to consider the number of ATP molecules produced from the citric acid cycle.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the number of ATP molecules produced from the oxidation of fatty acids is directly related to the chain length of the fatty acid. Longer-chain fatty acids produce more ATP molecules due to the increased number of NADH and FADH2 molecules generated.
**Correct Answer:** D. 36.