The structure of tripeptide will be as followed at PH = 2 (in highly acidic medium)

Answer

5

Explanation

The structrure of tripeptide will be as followed at PH = 2 (in highly acidic medium)

Hence `|z_1| = 2` at pH = 6 (in approximately neutral solution it will be)

Hence `|z_2| = 0` at pH = 11 (in highly basic medium) the structure will be

Hence `|z_3|` will be 3.
Therefore, `|z_1| + |z_2| + |z_3| = 2 + 0 + 3 = 5`.