On the other hand, if we don't have many ATP molecules in a cell then we have a low energy charge value, so low ratio and we have many more amp molecules and they will bind onto the phosphorptokinase and essentially activate them. They will make them much more likely to actually convert the fructosex phosphate into the fructose one six biphosphate bisphosphate. So basically the takeaway lesson here is the same two alystaric molecules that are used by skeleton muscle cells to control phosphorinase is also used by liver cells. But there are many important differences. Difference number one, in skeleton muscle cells the PH actually affects the activity of phosphop fructokinase. So in our discussion previously we said that a low PH or a very acidic environment basically inactivates inhibits phosphoruxokinase in skeletal muscle cells and that's because in skeletal muscle cells as we exercise there can be a build up in lactic acid.