Review Questions

For each question, choose the ONE BEST answer or completion.

1. Peptide bonds result from

A. the reaction of amino groups with water.

B. the reaction of two carboxyl groups and removal of water.

C. the reaction of an amino group with a carboxyl group and loss of water.

D. reactions between amino acid side chains.

E. transfer of a phosphate group from ATP to the amino acid.

2. The amino acids found in proteins are called

A. a amino acids.

B. 6 amino acids.

C. y amino acids.

D. S amino acids.

E. n amino acids.

3. The side chains of the amino acids serine, asparagine, and glutamine are all

A. normally negatively charged at pH 7.

B. normally positively charged at pH 7.

C. able to interact with water.

D. hydrophobic.

E. indifferent to their environment.

4. The amino acids making up an a helix

A. have side chains that point outward—away from the center of the helix.

B. have side chains that point inward—making up a hydrophobic core for the helix.

C. have side chains that do not interact with amino acids elsewhere in the protein.

D. have side chains that are always hydrophobic.

E. include proline.

5. Disulfide bonds

A. form between two methionine residues.

B. form between two cystine residues.

C. form between two cysteine residues.

D. are found in cytoplasmic proteins.

E. attach microtubules to organelles.

6. Integral membrane proteins are helped to locate across the lipid bilayer by

A. glycosylation.

B. formation of disulfide bonds.

C. phosphorylation.

D. using an a helix made up of amino acids with hydrophilic side chains.

E. using an a helix made up of amino acids with hydrophobic side chains.

7. Proteins cannot usually be denatured by

A. concentrated urea solutions.

B. oxygen.

C. strong acid.

D. concentrated ethanol solutions.

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