So we have an enzyme known as galactokinase. And what a galactokinase does, well, it's a kinase, so it has to use an ATP and it basically transfers a phosphoryl group from that ATP onto carbon number one of galactose, and we form galactose one phosphate. So one phosphoryl from the ATP onto this oxygen here to form this galactose one phosphate. We form the ATP and the H plus. Now, what this does is, again, it traps it inside the cell and destabilizes it in the next step. Step number two, we have an enzyme known as galactose one phosphate because this is a substrate that it acts on and it's a urinal transferase.