So if we put these two together, we see that because at the normal physiological PH, this will be negatively charged, and this will be positively charged, these two charges will essentially cancel out. And so the net charge on that amino acid at the normal physiological PH will depend on the charge that is found on that side chain group. And remember, a zwitter ion or a dipolar form of the amino acid basically means it will exist with this negative charge and this positive charge. Now, let's actually focus on the seven amino acids that have ionized the bulk side chain groups. So let's begin with aspartic acid and glutamic acid. Now, both of these acids, both of these amino acids contain a side chain group that contains a carboxylic acid.