And these beads are usually made from some type of carbohydrate polymer, such as cellulose. Okay, so in this lecture, we're going to focus on this setup. So let's zoom in on one of these, or let's zoom in on a small section of our column. We get the following diagram. So, these blue beads are our negatively charged cellulose beads, as shown in the following diagram. Now, let's suppose we want to separate a mixture of three different proteins, and these proteins differ from one another based on their net charge.