\[\begin{array}{l} \text { Exhibit } \mathbf { 3 A } \text { (for this chapter) }\\ \begin{array} { l l l l } \text { Amino acid } & \boldsymbol { \alpha } \text {-carboxyl group pK a } & \boldsymbol { \alpha } \text {-amino group pK a } & \text { R-group pK } \\ \hline \text { Ala } & 2.3 & 9.7 & \\ \text { Arg } & 2.2 & 9.0 & 12.5 \\ \text { Asn or Gln } & 2.1 & 9.0 & 4.0 \\ \text { Asp or Glu } & 2.2 & 9.8 & 8.3 \\ \text { Cys } & 1.7 & 10.8 & 6.0 \\ \text { His } & 1.8 & 9.2 & \\ \text { Ser } & 2.2 & 9.2 & 10.1 \end{array} \end{array}\] -Refer to Exhibit 3A. The pI of the peptide ALA-GLN-ARG-SER-HIS would be:

A) Strongly acid B) Weakly acid (4-6) C) About neutral (6-8) D) Weakly basic (8-10) E) Strongly basic A) Strongly acid B) Weakly acid (4-6) C) About neutral (6-8) D) Weakly basic (8-10) E) Strongly basic

\[\begin{array}{l} \text { Exhibit } \mathbf { 3 A } \text { (for this chapter) }\\ \begin{array} { l l l l } \text { Amino acid } & \boldsymbol { \alpha } \text {-carboxyl group pK a } & \boldsymbol { \alpha } \text {-amino group pK a } & \text { R-group pK } \\ \hline \text { Ala } & 2.3 & 9.7 & \\ \text { Arg } & 2.2 & 9.0 & 12.5 \\ \text { Asn or Gln } & 2.1 & 9.0 & 4.0 \\ \text { Asp or Glu } & 2.2 & 9.8 & 8.3 \\ \text { Cys } & 1.7 & 10.8 & 6.0 \\ \text { His } & 1.8 & 9.2 & \\ \text { Ser } & 2.2 & 9.2 & 10.1 \end{array} \end{array}\] -Refer to Exhibit 3A. Which of these amino acids could act as a good buffer at pH = 4.5

A) Alanine B) Arginine C) Asparagine D) Cysteine E) Aspartic Acid A) Alanine B) Arginine C) Asparagine D) Cysteine E) Aspartic Acid

\[\begin{array}{l} \text { Exhibit } \mathbf { 3 A } \text { (for this chapter) }\\ \begin{array} { l l l l } \text { Amino acid } & \boldsymbol { \alpha } \text {-carboxyl group pK a } & \boldsymbol { \alpha } \text {-amino group pK a } & \text { R-group pK } \\ \hline \text { Ala } & 2.3 & 9.7 & \\ \text { Arg } & 2.2 & 9.0 & 12.5 \\ \text { Asn or Gln } & 2.1 & 9.0 & 4.0 \\ \text { Asp or Glu } & 2.2 & 9.8 & 8.3 \\ \text { Cys } & 1.7 & 10.8 & 6.0 \\ \text { His } & 1.8 & 9.2 & \\ \text { Ser } & 2.2 & 9.2 & 10.1 \end{array} \end{array}\] -Refer to Exhibit 3A. Calculate the pI of CYS?

A) 1.7 B) 5.0 C) 8.3 D) 9.6 E) 10.8 A) 1.7 B) 5.0 C) 8.3 D) 9.6 E) 10.8

A) is planar B) can be written as a resonance hybrid C) is the basis of protein structure. D) all of the above A) is planar B) can be written as a resonance hybrid C) is the basis of protein structure. D) all of the above

A) are cyclic compounds in the chair form. B) are not superimposable on their mirror images. C) never occur in nature. D) do not form crystals. A) are cyclic compounds in the chair form. B) are not superimposable on their mirror images. C) never occur in nature. D) do not form crystals.

\[\begin{array}{l} \text { Exhibit } \mathbf { 3 A } \text { (for this chapter) }\\ \begin{array} { l l l l } \text { Amino acid } & \boldsymbol { \alpha } \text {-carboxyl group pK a } & \boldsymbol { \alpha } \text {-amino group pK a } & \text { R-group pK } \\ \hline \text { Ala } & 2.3 & 9.7 & \\ \text { Arg } & 2.2 & 9.0 & 12.5 \\ \text { Asn or Gln } & 2.1 & 9.0 & 4.0 \\ \text { Asp or Glu } & 2.2 & 9.8 & 8.3 \\ \text { Cys } & 1.7 & 10.8 & 6.0 \\ \text { His } & 1.8 & 9.2 & \\ \text { Ser } & 2.2 & 9.2 & 10.1 \end{array} \end{array}\] -Refer to Exhibit 3A. What is the order of the pIs in increasing order (from acid to base)?

A) Alanine, Arginine, Asparagine, Cysteine, and Aspartic Acid B) Aspartic Acid, Alanine, Asparagine, Cysteine, and Arginine C) Aspartic Acid, Cysteine, Asparagine, Alanine, and Arginine D) Arginine, Alanine, Asparagine, Cysteine, and Aspartic Acid E) Aspartic Acid, Cysteine, Arginine, Alanine, and Asparagine, A) Alanine, Arginine, Asparagine, Cysteine, and Aspartic Acid B) Aspartic Acid, Alanine, Asparagine, Cysteine, and Arginine C) Aspartic Acid, Cysteine, Asparagine, Alanine, and Arginine D) Arginine, Alanine, Asparagine, Cysteine, and Aspartic Acid E) Aspartic Acid, Cysteine, Arginine, Alanine, and Asparagine,