Now, Lysine, Arginine, and histidine are basic amino acids. And what that means is their side chain groups at the normal physiological PH bears a full positive charge. On the other hand, aspartate and glutamate are the two acidic amino acids. 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.