Principle #17 Every effect has a cause and every cause has effects

Life is full of cause and effect reactions. Life at the cellular level is certainly no different. The TCA cycle is a very important chain of events that creates a large amount of energy that our body will need to survive. This chain of events is very closely regulated so that too much energy is not created and so that energy is created when the body is running low on energy.

These points of regulation are managed by product feedback. Pyruvate Dehydrogenase is the first regulator enzyme. When PDH performs its reaction, it will change pyruvate to acetyl CoA, this process will produce NADH or energy. This enzyme is regulated by this product, along with some others. If there is a high amount of NADH present then the effect of this would be to slow the TCA cycle down. If there is low NADH the cycle will speed up, thus producing more NADH.