And what a transferase does is it basically transfers some type of group from one molecule onto a different molecule. Now, aside from having the galactose one phosphate, another molecule known as UDP glucose actually comes in. So this is a modified glucose molecule that contains a uridine diphosphate. So essentially attached onto carbon number one of glucose, we have the uradine diphosphate group. And what this transferase enzyme does is it transfers up a sporal group from the urine diphosphate glucose onto this phosphate region here. And so we go from galactose one phosphate to UDP galactose.