Now, in the same analogous way that gluconeogenesis, the building of glucose molecules and glycolysis the breaking down of glucose molecules, in the same analogous way that these two processes are not simply the reverse of one another, we see that glycogen synthesis is not simply the reverse of the breakdown of glycogen. In fact, as we'll see in this lecture, glycogen synthesis actually follows a completely different reaction pathway when it uses the glucose precursors to actually build the glycogen polysaccharide. Now, there are two important processes that we have to consider when actually building the glycogen. Before we can actually take the glucose and attach the glucose onto that growing glycogen polymer, we have to make that glucose a reactive molecule, because glucose by itself, and more specifically, glucose one phosphate, is not reactive enough, it's not high in energy to basically attach itself onto that glycogen chain. What we have to do before anything is actually activate that glucose molecule. And by activating, I mean we have to make it more reactive, we have to increase its energy.