Remember, what the PKA means is if the PH is equal to the PKA, then that is the point at which half of these molecules are deprotonated and half of them are protonated. So if we're below the PKA of ten at the physiological PH of seven, that means all of these Lysine amino acids will be protein. It will have a full positive charge on the nitrogen. That's exactly what makes Lysine a basic amino acid. It has a full positive charge on that side chain group. Now, let's move on to Arginine.