C) what is the overall charge of the most abundant tripeptide species at neutral ph (ph 7.0) ?

A compound, expecially with numerous functional groups, can have a lot of pKa and pKb charges. These are the individual acidic (pKa) and basic (pKb) charges of each functional group in the compound. These charges affect one another due to electrostatic attractions. When you want to find the net charge or the overall charge of the compound, you have to test it by using a pH meter. If the pH you get is 7, then it is neutral. The range of pH is between 1 to 14. pH's 1 to 6 are acidic, and pH's 8 to 14 are basic. The neutral pH is at pH 7 like pure water. That means that the overall charge is 0.