There is no net synthesis of 4-carbon precursors of glucose during the metabolic breakdown of acetyl-CoA in the TCA cycle because of which of the following reason? A) insufficient NADH for gluconeogenesis is produced in the mitochondrial matrix during oxidation-reduction reactions of the cycle B) the mitochondrial membrane is impermeable to oxaloacetate which is trapped in the matrix C) oxidative decarboxylation reactions prevent oxaloacetate production by producing allosteric inhibitors D) 2 moles of CO₂ are released during each circuit of the cycle

Question

Quizplus · Accepted Answer

During each turn of the TCA cycle, two molecules of CO2 are released, which balances the carbons entering the cycle as acetyl-CoA, preventing net synthesis of 4-carbon precursors.

There Is No Net Synthesis of 4-Carbon Precursors of Glucose