Moles ATP produced by complete breakdown of one mole of fat?

• A. 460
• B. 100
• C. 360
• D. 80

Answer: (A)

Fat yields a large amount of energy because fatty acids are highly reduced carbon chains that, when oxidized, produce many acetyl-CoA units along with NADH and FADH2 that feed the electron transport chain. A typical fat molecule is a triglyceride, with three fatty acid chains and a glycerol backbone. When this molecule is completely oxidized, the fatty acid chains provide substantial acetyl-CoA for the TCA cycle and a large supply of reducing equivalents for oxidative phosphorylation, giving a total around 460 ATP. The exact value depends on the length of the fatty acids, but 460 ATP is the conventional rounded figure used in this context for a complete fat breakdown. The smaller numbers would reflect energy yields from carbohydrates or shorter fats, not from a full fat oxidation.