Group the amino acids in Problem 32 according to whether they are 

(a) Positively charged, 

(b) Neutral, 

(c) Negatively charged at pH = 7.

Data From Problem 32

(a) Alanine at pH = 1, 7, and 12;

(b) Serine at pH = 1, 7, and 12; 

(c) Lysine at pH = 1, 7, 9.5, and 12; 

(d) Histidine at pH = 1, 5, 7, and 12; 

(e) Cysteine at pH = 1, 7, 9, and 12; 

(f) Aspartic acid at pH = 1, 3, 7, and 12; 

(g) Arginine at pH = 1, 7, 12, and 14; 

(h) Tyrosine at pH = 1, 7, 9.5, and 12.