Because if the side chain groups can form ions, the ions have full charges, and those charges can participate in forming ionic bonds with other macromolecules. So that's exactly what makes these seven amino acids reactive. And that's what gives them the ability to participate in a variety of different types of biological reactions that take place inside our bodies. So what are these seven amino acids? So we have aspartic acid and glutamic acid, Aratu, acidic amino acids, and the rest are histidine, cysteine, lysine, tyrosine, and arginine. Now, on top of these ionizable side chain groups found on these seven amino acids, every one of our amino acids also contains ionizable alphacroboxyl groups and ionizable alpha amino group.