Tripalmitin is a TAG formed by the esterification of glycerol with three palmitic acid molecules. How many acetyl CoA molecules will be produced by the complete oxidation of tripalmitin? (Hint: consider glycerol metabolism too).

• A. 22
• B. 24
• C. 25
• D. 26

Answer: (C)

Verified step by step guidance

1. Understand the structure of tripalmitin: It is a triacylglycerol (TAG) composed of glycerol and three palmitic acid molecules. Each palmitic acid is a 16-carbon fatty acid.
2. Calculate the number of acetyl CoA molecules produced from the oxidation of one palmitic acid: Each palmitic acid undergoes beta-oxidation, which involves several cycles. Each cycle shortens the fatty acid chain by two carbons, producing one acetyl CoA. For a 16-carbon palmitic acid, this results in 8 acetyl CoA molecules.
3. Determine the total acetyl CoA from the three palmitic acids: Since each palmitic acid yields 8 acetyl CoA, three palmitic acids will produce 3 x 8 = 24 acetyl CoA molecules.
4. Consider the metabolism of glycerol: Glycerol is converted into dihydroxyacetone phosphate (DHAP) and then enters glycolysis, eventually producing one acetyl CoA molecule.
5. Add the acetyl CoA from glycerol to the total from palmitic acids: The 24 acetyl CoA from the palmitic acids plus 1 acetyl CoA from glycerol results in a total of 25 acetyl CoA molecules produced from the complete oxidation of tripalmitin.