How many molecules of ATP are formed during the complete catabolism of a saturated fatty acid with the chemical formula CH₃(CH₂)₂₀CO₂H?

Question

Quizplus · Accepted Answer

The given formula for the saturated fatty acid is C13H26O2, which indicates a 12-carbon chain fatty acid (since the first carbon is part of the carboxyl group). The complete catabolism of a saturated fatty acid through beta-oxidation involves the breakdown of the fatty acid into two-carbon acetyl-CoA units, which then enter the citric acid cycle. Each round of beta-oxidation generates 1 FADH2, 1 NADH, and 1 acetyl-CoA (except the last round which only produces an additional acetyl-CoA without further beta-oxidation). For a 12-carbon fatty acid:- Beta-oxidation occurs (12/2) - 1 = 5 times.- This produces 5 FADH2, 5 NADH, and 6 acetyl-CoA (since the last round gives 2 acetyl-CoA).Each FADH2 yields 1.5 ATP, each NADH yields 2.5 ATP (in the electron transport chain), and each acetyl-CoA yields 10 ATP when processed through the citric acid cycle. Therefore, the total ATP yield is:- From FADH2: 5 * 1.5 = 7.5 ATP- From NADH: 5 * 2.5 = 12.5 ATP- From acetyl-CoA: 6 * 10 = 60 ATPThe total ATP yield is 7.5 + 12.5 + 60 = 80 ATP. However, this calculation does not account for the ATP investment in activating the fatty acid (2 ATP), so the net yield is 80 - 2 = 78 ATP. The options provided do not match this calculation, suggesting a misunderstanding in the calculation process or a mistake in interpreting the question's requirements. Given the options, none directly match the calculated value, indicating a need to reassess the calculation or the question's interpretation.

How Many Molecules of ATP Are Formed During the Complete