Moles ATP produced by complete breakdown of one mole of glycogen under anaerobic conditions?

Moles ATP produced by complete breakdown of one mole of glycogen under anaerobic conditions?

• A. 4
• B. 6
• C. 10
• D. 2

Answer: (D)

In anaerobic metabolism, energy comes from glycolysis, which for each glucose molecule provides 2 ATP. When glycogen is the starting source, the breakdown to glucose-6-phosphate by glycogenolysis bypasses the initial ATP‑consuming step, so per glucose unit entering glycolysis you can net 3 ATP instead of 2. However, a mole of glycogen is a polymer made up of many glucose units, so the total ATP produced isn’t a fixed number without knowing how many glucose units are in that mole of glycogen. In other words, the amount of ATP depends on the size of the glycogen molecule; you’d have 3 ATP per glucose unit, multiplied by how many glucose units are present. The key idea is that glycogen yields more ATP per glucose unit under anaerobic conditions than free glucose, but the exact total depends on glycogen’s length.

In anaerobic metabolism, energy comes from glycolysis, which for each glucose molecule provides 2 ATP. When glycogen is the starting source, the breakdown to glucose-6-phosphate by glycogenolysis bypasses the initial ATP‑consuming step, so per glucose unit entering glycolysis you can net 3 ATP instead of 2. However, a mole of glycogen is a polymer made up of many glucose units, so the total ATP produced isn’t a fixed number without knowing how many glucose units are in that mole of glycogen. In other words, the amount of ATP depends on the size of the glycogen molecule; you’d have 3 ATP per glucose unit, multiplied by how many glucose units are present. The key idea is that glycogen yields more ATP per glucose unit under anaerobic conditions than free glucose, but the exact total depends on glycogen’s length.