If the 16-carbon saturated fatty acid palmitate is oxidized completely to carbon dioxide and water (via the $\beta$-oxidation pathway and the citric acid cycle),and all of the energy-conserving products are used to drive ATP synthesis in the mitochondrion,the net yield of ATP per molecule of palmitate is:

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The complete oxidation of palmitate involves the breakdown of the molecule into 8 acetyl-CoA units, which then enter the citric acid cycle (also known as the Krebs cycle) where they undergo further oxidation to produce reduced coenzymes NADH and FADH2. The NADH and FADH2 produced in the citric acid cycle are then used to generate ATP via oxidative phosphorylation in the electron transport chain. The net yield of ATP per molecule of palmitate is therefore much higher than for glucose or other sugars, since palmitate is a long-chain fatty acid with many carbons to oxidize.

The complete oxidation of palmitate can be summarized as follows:

Palmitate + 23 O2 → 16 CO2 + 16 H2O + energy (ATP)

- Each cycle of beta-oxidation yields 1 molecule of acetyl-CoA, 1 molecule of NADH, and 1 molecule of FADH2.
- In the citric acid cycle, each molecule of acetyl-CoA yields 3 molecules of NADH, 1 molecule of FADH2, and 1 molecule of ATP (via substrate-level phosphorylation).
- The NADH and FADH2 produced in the citric acid cycle are then used to generate ATP via oxidative phosphorylation in the electron transport chain. The net yield of ATP from oxidative phosphorylation depends on the number of protons (H+) that are pumped across the inner mitochondrial membrane by the electron transport chain, which varies depending on the specific carrier proteins involved. However, on average, the yield is about 2.5 ATP molecules per NADH and 1.5 ATP molecules per FADH2.

Therefore, the net yield of ATP per molecule of palmitate can be calculated as follows:

- 8 cycles of beta-oxidation yield 8 molecules of acetyl-CoA, 8 molecules of NADH, and 8 molecules of FADH2.
- 1 molecule of acetyl-CoA yields 3 molecules of NADH, 1 molecule of FADH2, and 1 molecule of ATP (via substrate-level phosphorylation) in the citric acid cycle.
- Therefore, 8 molecules of acetyl-CoA yield 24 molecules of NADH, 8 molecules of FADH2, and 8 molecules of ATP.
- The 24 molecules of NADH and 8 molecules of FADH2 are then used to generate ATP via oxidative phosphorylation. Assuming an average yield of 2.5 ATP molecules per NADH and 1.5 ATP molecules per FADH2, this generates a total of (24 x 2.5) + (8 x 1.5) = 66 ATP molecules.
- Adding the 8 ATP molecules generated via substrate-level phosphorylation in the citric acid cycle gives a total of 74 ATP molecules.
- Finally, 2 ATP molecules are expended during the activation of palmitate to form palmitoyl-CoA, so the net yield of ATP per molecule of palmitate is 74 - 2 = 72 ATP molecules.

If the 16-Carbon Saturated Fatty Acid Palmitate Is Oxidized Completely β\betaβ

If the 16-Carbon Saturated Fatty Acid Palmitate Is Oxidized Completely $\beta$