Which statement about fatty acid metabolism is true?

Which statement about fatty acid metabolism is true?

• A. Fatty acid synthesis occurs in the mitochondria.
• B. Fatty acid breakdown occurs in the cytosol.
• C. Beta-oxidation produces acetyl-CoA and reduces FAD and NAD+.
• D. Beta-oxidation yields CO2 directly.

Answer: (C)

Fatty acid metabolism involves breaking down fats to harvest energy, with the key step being beta-oxidation that occurs mainly in mitochondria (and in peroxisomes for very long chains). In each cycle of beta-oxidation, the fatty acyl-CoA is split to release a two-carbon acetyl-CoA unit and pass electrons to carriers, producing FADH2 and NADH. This combination—acetyl-CoA plus the reduced carriers—is what makes the statement true: beta-oxidation yields acetyl-CoA and reduces FAD and NAD+. The acetyl-CoA then feeds the TCA cycle to generate more energy, and CO2 is released later in the cycle, not directly during beta-oxidation. By contrast, fatty acid synthesis occurs in the cytosol (not mitochondria) and does not produce CO2 directly in the breakdown steps.

Fatty acid metabolism involves breaking down fats to harvest energy, with the key step being beta-oxidation that occurs mainly in mitochondria (and in peroxisomes for very long chains). In each cycle of beta-oxidation, the fatty acyl-CoA is split to release a two-carbon acetyl-CoA unit and pass electrons to carriers, producing FADH2 and NADH. This combination—acetyl-CoA plus the reduced carriers—is what makes the statement true: beta-oxidation yields acetyl-CoA and reduces FAD and NAD+. The acetyl-CoA then feeds the TCA cycle to generate more energy, and CO2 is released later in the cycle, not directly during beta-oxidation. By contrast, fatty acid synthesis occurs in the cytosol (not mitochondria) and does not produce CO2 directly in the breakdown steps.