 So there is a wealth of information you can do here. I'm gradually going to leave protein folding, but there are two parts that I want to touch on briefly. The first one is that we haven't solved the wave in part yet. I haven't forgotten that. But if you look at that Chevron plot, it's not quite as easy as in the ideal case. So it typically looks like this, but once we move up here, the curve doesn't continue. At some point, it doesn't go faster anymore. And that's strange because here I would expect folding to dominate, and I've removed all the chemical denaturation or something. It should be great. Why doesn't it want to continue to fold? That has to do with misfolded states, which is so much interesting when we talk about prions, for instance. So what happens here is that normally you would have, let's say that we have an energy diagram, and we're starting out here, here's my unfolded state. There are a bunch of misfolded states here. They're not necessarily multi-globular, so I have to call them misfolded. And they have a beautiful native state here. So there are two things that can happen here. I can end up there by mistake, but that's not going to be too bad because I have an uphill barrier to go there, which means that I will likely pretty quickly go back to my unfolded state. And then at some point, I'm going to fold down to my native state. So as soon as the native state is quite stable here, I'm going to start having a nice, clean, fast-folding process. As you're reducing the temperature here, what will happen is likely that my native state is even happier. At some point, my native state is going to be down here. Now it's going to fold even quicker. I haven't bothered drawing the energy barrier here, but you just have to trust me that the energy barrier likely drops too. So that's great. Shouldn't you just keep reducing the amount of the naturant here? Well, what will happen at some point is the following. Suddenly I am here, and I have my unfolded state, and I still have the native, and I have the new native state that's called in prime. That's even lower. But what has now happened is that some of my misfolded states have a negative free energy. So what now happens is that some of these will go down here. It's downhill. It's going to be great to end up there. But for those to go back, they might now need to move uphill. That's going to be slow. So what happens here, the reason why it's slower to go to the native state is that the misfolded states or intermediates, whatever you call them, things that I don't want to end up in, have also become too stable. And then the process actually ends up going a bit slower. So again, these seemingly simple plots tell us huge amounts of valuable information about how the molecular process happens. Now it's time to revisit Leventhal.