So a method called affinity chromatography basically separates, allows us to purify and isolate specific type of protein molecules from within a mixture of proteins based on their affinity to bind to specific molecules. Now, just like in gel filtration chromatography, an ion exchange chromatography, we also have the same exact setup in affinity chromatography. So we have a funnel. We place the funnel on top of a long, narrow column, and inside that column, we pack that column with these insoluble gel beads. Now, in the case of affinity chromatography, what we want to do is we basically want to modify those gel beads and we want to attach a specific type of group or molecule onto those gel beads. For example, if we zoom in on one of these gel beads, we get the following diagram and notice that to the gel bead.