A single glucose molecule can yield a large amount of ATP when oxygen is present. This makes aerobic respiration the most energy-rich pathway. ATP Breakdown Glycolysis: 2 ATP Krebs cycle: 2 ATP Electron Transport Chain: 32–34 ATP Total: Around 36 - 38 ATP molecules per glucose. This is nearly 18 times more energy than anaerobic respiration, which makes only 2 ATP.