So many prokaryotic and eukaryotic organisms undergo lactic acid fermentation. In fact, when the two supply runs low in our cells they use this process to regenerate the NAD plus. And this process is a single step process that essentially consists of a well, not a single step process but it's more complicated than that. But we can think of it as being one step in the sense that here we have two steps but here we have one step. So essentially this process is catalyzed by an enzyme known as lactate dehydrogenase. And again, just like this dehydrogenase and the dehydrogenase that was used in step six of glycolysis.