Three Systems Regulate Energy Production

All three systems regulate energy production as they help create ATP. The creatine phosphate system is the first system mentioned as it is the quickest of the systems. In this system, there is a reversible reaction, where phosphocreatine and ADP form ATP and creatine. This reaction happens quickly and therefore the system does not provide long lasting energy; however, there is a large amount of energy production in this short amount of time. Activity beyond a few seconds requires more substantial energy production, as with anaerobic glycolysis. In anaerobic glycolysis, glucose is transformed into pyruvate and 2 net ATP are also produced. There is enough ATP production for about 2 minutes of activity. Also, 2 NADH are produced that are then

used in the electron transport chain. The pyruvate from anaerobic glycolysis can either be transformed (lactate and eventually back to glucose) or used in the Krebs cycle. Pyruvate is converted into acetyl CoA before entering the Krebs cycle. Glucose is not the only substance that can enter the Krebs cycle; fatty acids are also converted into acetyl CoA and amino acids can enter the cycle at almost any point. For each pyruvate that enters the cycle, 3 NADH and 1 FADH are produced and used in the electron transport chain. After the Krebs cycle, NADH and FADH act as electron carriers in the electron transport chain. In the electron transport chain, electrons are sent back and forth along a hydrogen gradient in order to power ATP synthase. This is a very efficient system and many ATP are formed during the transfer. The systems also regulate energy usage as they require some ATP in order to function correctly. While there is a net gain of ATP, there are several regulators throughout the systems to guarantee that there is not an abundance or depletion of any molecules used. Rate limiting enzymes are vital to ensure that the systems are moving at the correct speeds. Overall, the systems work together, even if they provide ATP at different rates.