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. One of the reasons is because we want to trap that glucose inside the cytoplasm. We want to keep that glucose from exiting our cell. And by adding this negatively charged phosphate group, we basically keep that glucose inside the cytoplasm because it no longer is capable of being transported across our cell membrane.