What is the typical net ATP yield from cellular respiration?

What is the typical net ATP yield from cellular respiration?

• A. 100 ATP
• B. 10 ATP
• C. 2 ATP
• D. 36-38 ATP

Answer: (D)

Cellular respiration packages energy from glucose into ATP through both substrate-level phosphorylation and oxidative phosphorylation. When you total the ATP produced across all stages under common assumptions about the efficiency of the electron transport chain, the figure that’s often cited is about 36–38 ATP per glucose. This comes from adding the 4 ATP generated directly by substrate-level phosphorylation (2 from glycolysis and 2 from the citric acid cycle) plus the ATP equivalent from NADH and FADH2 fed into the electron transport chain (roughly 2–3 ATP per NADH and about 2 ATP per FADH2, depending on the shuttle and organism). In many real cells, the exact number can be a bit lower because NADH produced in glycolysis needs shuttles to reach mitochondria, which can reduce the practical yield to around 30–32 ATP. Still, the 36–38 ATP figure is the traditional, widely taught estimate for the net ATP yield per glucose in cellular respiration.

Cellular respiration packages energy from glucose into ATP through both substrate-level phosphorylation and oxidative phosphorylation. When you total the ATP produced across all stages under common assumptions about the efficiency of the electron transport chain, the figure that’s often cited is about 36–38 ATP per glucose. This comes from adding the 4 ATP generated directly by substrate-level phosphorylation (2 from glycolysis and 2 from the citric acid cycle) plus the ATP equivalent from NADH and FADH2 fed into the electron transport chain (roughly 2–3 ATP per NADH and about 2 ATP per FADH2, depending on the shuttle and organism). In many real cells, the exact number can be a bit lower because NADH produced in glycolysis needs shuttles to reach mitochondria, which can reduce the practical yield to around 30–32 ATP. Still, the 36–38 ATP figure is the traditional, widely taught estimate for the net ATP yield per glucose in cellular respiration.