And the second thing we have to understand is glucose one phosphate. So the glucose molecule that we ultimately want to actually add onto that growing glycogen chain is not reactive enough to actually attach onto it. What we have to do is we have to first activate it. And the way that we activate that glucose one phosphate is by reacting it with the urine triphosphate UTP molecule. What that does is it adds an additional charge onto it and it makes this Esther bond much more reactive. And so when this process takes place, this can act as a strong nucleophile to this good electrophile.