Final answer:
ATP production per glucose in the liver and heart during aerobic respiration is theoretically around 30-32 ATPs, with variances due to electron transport efficiency differences. In skeletal muscles, during intense exercise and anaerobic conditions, only 2 ATPs are generated per glucose via glycolysis.
Step-by-step explanation:
The amount of ATP produced per glucose molecule during cellular respiration varies between different tissues in the body, such as the liver, heart, and skeletal muscles. In aerobic respiration, which includes glycolysis, the Krebs cycle, and the electron transport chain, a theoretical maximum of approximately 30-32 ATP molecules can be produced in tissues like the liver where NAD* is the primary electron transporter. Glycolysis produces a net of 2 ATPs, while the Krebs cycle generates another 2 ATPs. The electron transport chain, powered by NADH and FADHâ‚‚ from these earlier stages, provides the bulk of the ATP.
For the heart and skeletal muscles, the yield may be slightly different due to variation in the efficiency of electron transport and the type of shuttle used to get electrons into the mitochondria. The liver utilizes NAD* as the primary electron transporter, whereas other tissues, such as the brain, rely on FAD*. If considering anaerobic glycolysis, which occurs when oxygen is limited (as can happen in overworked skeletal muscles), only 2 ATP molecules are produced per glucose molecule since the process ends with glycolysis.
The stored ATP in resting muscles is used up in seconds and more ATP is generated from creatine phosphate for about 15 seconds, then muscles rely on glycolysis and aerobic respiration. Aerobic respiration is the primary source of ATP for resting or moderately active muscles, accounting for approximately 95 percent of the ATP required. During strenuous exercise, when oxygen delivery is insufficient, pyruvate from glycolysis is converted to lactic acid, which can contribute to muscle fatigue.