The energy cost of gluconeogenesis
How many high-energy phosphate bonds (ATP plus GTP) are used to make one glucose from two pyruvate?
Answer C: explanation for every choice
A
2 is the net ATP yield of glycolysis. Gluconeogenesis costs more than glycolysis produces.
B
This counts only the ATP and misses the 2 GTP used by PEP carboxykinase.
C
Correct. Pyruvate carboxylase uses 2 ATP, PEP carboxykinase 2 GTP, and phosphoglycerate kinase 2 ATP.
D
This counts each step twice, as if each pyruvate required 6.
TakeawayGluconeogenesis: 4 ATP + 2 GTP + 2 NADH per glucose.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb162.