Exam 3: Protein Structure and Function

The R-group, or side chain, of the amino acid serine is -CH2-OH. The R-group, or side chain, of the amino acid leucine is -CH2-CH-(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution?

Side chains of amino acids ________.

At about pH 7 in most cells, what happens to the carboxyl R-group on an amino acid?

Amino acids are acids because they always possess which functional group?

The following question(s) are based on the 15 molecules illustrated in the accompanying figure. Each molecule may be used once, more than once, or not at all. -Which of the following pairs of molecules could be joined together by a peptide bond in a dehydration reaction?

The chemical reaction illustrated in the accompanying figure ________.

Which of the following involves an increase in entropy?

Refer to the accompanying figure to answer the following question(s). -Which bond is closest to the amino group of the molecule?

The bonding of two amino acid molecules to form a larger molecule requires the ________.

The tertiary structure of a protein is the ________.

Refer to the figure. Which level of structure is maintained by the disulfide bond?

An enzyme has a total of four active sites. When you denature the molecule and study its composition, you find that each active site occurs on a different polypeptide. Which of the following hypotheses does this observation support?

Refer to the accompanying figure to answer the following question(s). -At which bond would water need to be added to achieve hydrolysis of the peptide, back to its component amino acids?

Which level of protein structure do the α-helix and the β-pleated sheet represent?

If cells are grown in a medium containing radioactive 35S, which of these molecules will be labeled?

Refer to the accompanying figure to answer the following question(s). -Which bond is a peptide bond?

What is the location of the C-terminus of the protein in the figure?

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. What is the significance of this finding?

How does primary protein structure affect the function of protein enzymes?