So let's begin by looking at the details of stage one. So in Stage one, we take the glucose, we transport that glucose across the cell membrane into the cytoplasm of the cell. And then we use an enzyme known as Hexokinase to basically transform a glucose into glucose six phosphates. So we use an ATP molecule, we take a phosphate group from the ATP molecule and transfer it onto our glucose. So we form glucose six phosphate. Now, there are two reasons why we have to phosphorylate our glucose, why we have to add that phosphate group.