In aerobic energy production, which process is directly linked to oxidative phosphorylation that yields the most ATP per glucose molecule under normal conditions?

In aerobic energy production, which process is directly linked to oxidative phosphorylation that yields the most ATP per glucose molecule under normal conditions?

• A. Glycolysis
• B. Krebs cycle
• C. ATP-PC system
• D. Lactic acid system

Answer: (B)

In aerobic energy production, most ATP comes from oxidative phosphorylation, which uses the high-energy electrons carried by NADH and FADH2. The Krebs cycle is the main source of those reducing equivalents per glucose: two turns of the cycle yield 6 NADH and 2 FADH2 (plus 2 GTP). Those carriers feed the electron transport chain, where their electrons drive proton pumping and ATP synthase to generate the bulk of ATP—roughly 28–32 ATP per glucose depending on shuttle systems. Glycolysis provides some NADH and a small amount of ATP directly, but its contribution to oxidative phosphorylation is smaller, and the ATP-PC and lactic acid systems are anaerobic and supply energy only briefly. So the Krebs cycle is directly linked to oxidative phosphorylation and yields the most ATP per glucose under normal conditions.

In aerobic energy production, most ATP comes from oxidative phosphorylation, which uses the high-energy electrons carried by NADH and FADH2. The Krebs cycle is the main source of those reducing equivalents per glucose: two turns of the cycle yield 6 NADH and 2 FADH2 (plus 2 GTP). Those carriers feed the electron transport chain, where their electrons drive proton pumping and ATP synthase to generate the bulk of ATP—roughly 28–32 ATP per glucose depending on shuttle systems. Glycolysis provides some NADH and a small amount of ATP directly, but its contribution to oxidative phosphorylation is smaller, and the ATP-PC and lactic acid systems are anaerobic and supply energy only briefly. So the Krebs cycle is directly linked to oxidative phosphorylation and yields the most ATP per glucose under normal conditions.