If glucose is the sole energy source for cellular respiration in an animal, what proportion of the carbon dioxide exhaled is derived from oxidation of pyruvate to acetyl CoA?
A) 1/6
B) 1/3
C) 2/3
D) 100%

Question

Quizplus · Accepted Answer

During the conversion of pyruvate to acetyl CoA, one molecule of CO2 is released for each pyruvate molecule. Since glucose (a six-carbon molecule) is split into two three-carbon pyruvate molecules during glycolysis, and each pyruvate loses one carbon as CO2 in the transition to acetyl CoA, 2 out of the 6 carbons from the original glucose molecule are released as CO2 at this stage, which is 1/3 of the total carbon atoms.

If Glucose Is the Sole Energy Source for Cellular Respiration