And what that means is their side chains bear full negative charge at the normal physiological PH of around seven. So let's begin with Lysine. Now, Lysine contains the following relatively long side chain group. So we have 1234 of these carbon atoms, and each one of these carbon atom has two h atoms. Now, at the terminal end of the side group, we have a primary amino group. And what that means is we have a nitrogen that is bound to a single carbon, as shown in the following diagram.