And so if this molecule is not actually modified in any way, if we leave this molecule as it is, it will not be able to move on to stage three. And so what will happen is we will essentially lose the potential to form ATP molecules in stage three, because if this one is not modified, it cannot go on to stage three. And so in the next step, what happens is, as we'll see in just a moment, this one is actually transformed into this one via an isomerization reaction. So actually, these two molecules are, in fact isomer. So, once again, the glyceroaldehyde phosphate lies directly on the glycolytic pathway, which means it could go on directly into stage three to form the ATP molecules, the Pyruvate and the nadhs, as we'll see in the next lecture. But the dihydroxyantone phosphate does not lie on that pathway directly.