So what exactly are the details of step one and why does it actually take place? So let's suppose we have a glucose on the outside of the cell, and in the membrane of that cell, there's a special type of membrane protein that we're going to focus on in a future lecture that actually transports that glucose into the cytoplasm of that cell. Now, once that glucose is inside the cytoplasm of that cell, a special type of enzyme, a protein kinase we call hexokinase, actually catalyzes the addition of a phosphoryl group from an ATP molecule onto the carbon number six of this glucose. So this carbon number six basically gains a phosphoryl group as a result of the catalyzation of this hexokinase. Now we'll take a look at the details of hexokinase in just a moment. First, I'd like to answer the following question.