And that's because inside our body, we have a great diversity of proteins, and they vary in size. For example, we have various tiny proteins, such as insulin, which is only 51 amino acids in length. But we also have very, very large proteins, such as titan, also known as connectin, which is over 27,000 amino acids in length. So we have these proteins that vary in size, and we can use this property of size to basically separate and purify mixture of proteins. And one technique that we developed over the years to help us purify mixture of proteins based on size is gel filtration chromatography, also known as molecular exclusion chromatography. So let's begin by taking a look at the setup.