 So next lecture we're going to start looking specifically into the amino acid side chains and which ones are hydrophobic and hydrophilic, but there are both types. And what that means for a protein is that the second you throw a protein an amino acid side chain in water what's going to happen is exactly the same thing as for those liquid cyclohexanes. All the hydrophobic side chains will immediately want to turn themselves to the inside face and be away from water while the green ones in this case are going to be the water soluble ones that do face the water. So the green ones can participate in hydrogen bonds while the red ones can't. This is occasionally called the multenglobula. I'm a little bit hesitant of using that term. When I was your age we would have called this a multenglobula, but today we know more. Multenglobula is more of an intermediate state that's not completely random inside. So there is more protein structure, but for now consider this the first key state on the way towards protein folding and the multenglobula. But remember what I said about the hydrophobic effect being by far the largest part. That's true for proteins too. So it turns out that the hydrophobic effect accounts for almost everything in protein folding when it comes to delta G. We're going to gain most of the energy from this initial superfast collapse. And whilst that has happened the remaining energy is pretty much just polishing, some packing by van der Waals and our Joe's interactions. That might sound simple and it's not quite that simple because here I only spoke about delta G. This is true for the energetics of the process, but it doesn't mean that this explains 90 percent of the process. Just that you can have a very fast downhill initial slope due to the hydrophobic effect and this last 10 percent is going to be the really problematic part of the problem. So we didn't quite solve it. But the hydrophobic effect is the reason why we have a very clear inside of proteins and an outside of proteins just as hydrocarbons separate from water.