Structure and Properties of Peptides – Section 1

1. Hydrogen bonds in a-helices are

A. more numerous than Vander Waals interactions
B. not present at Phe residues
C. analogous to the steps in a spiral staircase
D. roughly parallel to the helix axis

Correct Answer: D. roughly parallel to the helix axis

2. The peptide bond in proteins is

A. only found between proline residues
B. usually cis unless proline is the next amino acid
C. usually trans unless proline is the next amino acid
D. is planar because of steric hindrance

Correct Answer: C. usually trans unless proline is the next amino acid

3. The molecular formula for glycine is C2H5O2N. What would be the molecular formula for a linear oligomer made by linking ten glycine molecules together by condensation synthesis?

A. C20H50O20N10
B. C20H32O11N10
C. C20H40O10N10
D. C20H68O29N10

Correct Answer: B. C20H32O11N10

4. Which of the following is an example of tertiary structure in a protein?

A. A multimeric protein
B. An a-helix
C. A P-pleated sheet
D. A globular domain

Correct Answer: D. A globular domain

5. The peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with cyanogen bromide (CNBr) to produce:

A. Val-Lys + Glu-Met-Ser + Trp-Arg-Ala
B. Val-Lys-Glu-Met-Ser-Trp + Arg-Ala
C. Val-Lys-Glu-Met + Ser-Trp-Arg-Ala
D. Val-Lys-Glu + Met-Ser-Trp-Arg-Ala

Correct Answer: C. Val-Lys-Glu-Met + Ser-Trp-Arg-Ala

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