31. The α-amino acids have a carboxyl group with a pK around __________ , and an amino group with a pK near __________ .

A. 1.1, and 12.1
B. 6.5, and 8.0
C. 3.3, and 10.5
D. 2.2, and 9.4

32. Coomassie Blue stains the proteins by reacting with

A. arginine residues
B. free c-termini
C. peptide bonds
D. aromatic ring

33. Which amino acid when exposed to ninhydrin produces a brown color?

A. Asparagine
B. Proline
C. Alanine
D. Valine