Question

We are now going to count the amount of ATPs that fat, sugar, and ethanol can produce per equivalent carbons. In this case, 12 carbons. We will compare sucrose, lauric acid, and six molecules of ethanol.Sucrose is cleaved to glucose and fructose by sucrase.How many ATP is produced from the COMPLETE oxidation of sucrose in the muscle. Assume 1NADH=3 ATP, 1FADH2=2ATP and 1 GTP= 1ATP

Answer 1

Both glucose and fructose are produced when cleaving sucrose, and both monosaccharides can enter glycolysis to obtain energy, then we have to sum the yield of glycolysis, TCA cycle and ETC.

- Glycolysis: This one yields 2 ATP, 2 NADH and 2 pyruvates per sugar molecule. Then our sucrose will yield 4 ATP, 4 NADH and 4 pyruvates.

- Transition reaction: This reaction yields 1 NADH and 1 acetyl CoA per pyruvate. Then our sucrose will yield 4 NADH and 4 acetyl CoA in this reaction

- TCA cycle: This one yields 3 NADH, one FADH2 and 1 GTP per acetyl CoA. Then our 4 acetyl CoA molecules will yield 12 NADH, 4 FADH2 and 4 GTP.

- ETC: This one will produce 3 ATP per NADH, 2 ATP per FADH2. We have a total of 20 NADH (4+4+12), a total of 4 FADH2, that will yield 60 ATP from NADH and 8 ATP from FADH2, plus the 4+4 ATP previously produced we end up with a total of:

60 + 8 + 4 +4 = 76 ATP final yield from our sucrose