How many times does the Citric Acid Cycle turn for one molecule of glucose?

How many times does the Citric Acid Cycle turn for one molecule of glucose?

• A. Once
• B. Twice
• C. Three times
• D. Four times

Answer: (B)

The Citric Acid Cycle, also known as the Krebs cycle or TCA cycle, turns twice for each molecule of glucose. This is because one glucose molecule is metabolized into two molecules of pyruvate during glycolysis. Each pyruvate then enters the mitochondria and is converted into acetyl-CoA before entering the Citric Acid Cycle. As each acetyl-CoA molecule combines with oxaloacetate to form citrate, it initiates one complete turn of the cycle. Since one glucose molecule yields two acetyl-CoA molecules, the cycle completes two rounds, allowing for the full oxidation of glucose to occur. This results in the production of energy carriers like NADH and FADH2, which are critical for ATP production in the subsequent electron transport chain. Thus, the correct answer emphasizes the stoichiometry of glucose metabolism through the cycle.

The Citric Acid Cycle, also known as the Krebs cycle or TCA cycle, turns twice for each molecule of glucose. This is because one glucose molecule is metabolized into two molecules of pyruvate during glycolysis. Each pyruvate then enters the mitochondria and is converted into acetyl-CoA before entering the Citric Acid Cycle.

As each acetyl-CoA molecule combines with oxaloacetate to form citrate, it initiates one complete turn of the cycle. Since one glucose molecule yields two acetyl-CoA molecules, the cycle completes two rounds, allowing for the full oxidation of glucose to occur. This results in the production of energy carriers like NADH and FADH2, which are critical for ATP production in the subsequent electron transport chain. Thus, the correct answer emphasizes the stoichiometry of glucose metabolism through the cycle.