Part One of the Question
PI of glycine is 5.97. It differs from glutamic acid since it has two hydrogens attached to the alpha carbon.
Part Two of the Question
Glutamic Acid pH is 2.19.
Adding an acid to a solution comprising the zwitterion, the carboxylate group arrests a hydrogen (H+) ion, and the amino acid becomes positively charged.
Adding a base, it removes an ion of the H+ ion from the amino group of the zwitterion produces a negatively charged amino acid.