So we have process one, process two, process three, and process four. So let's begin by focusing on process one. Now, in process one, we actually have two steps. In the first step, we want to take the ribose phosphosate molecule and transform it into an isomer version, ribulose phosphosphate. And this is actually the same reaction that we discussed in the previous lecture, except it's in reverse. And so we have the same enzyme as we discussed previously, phosphopentose isomerase that catalyzes this reaction.