And so if each one of these enzymes itself carries out some type of reaction, the protein kinase, by activating all these other enzymes, basically amplifies the result. It amplifies all these different types of reactions and that greatly speeds up the number of substrate molecules which are transformed to the product molecules. And we'll discuss this in much more detail in a future lecture. So activated protein kinases can be used to regulate many different enzymes and many different reaction pathways. And this can lead to an amplification effect in which we essentially amplify the amount of final product that we produce. Now, number six is whenever this reaction takes place because essentially what we're doing is we're defosphorylating this ATP molecule and the breakdown of the ATP molecule is a very exergonic reaction.