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Problem 1a
Classify each of the following proteins according to its function:
a. hemoglobin, oxygen carrier in the blood
Problem 1c
Classify each of the following proteins according to its function:
c. keratin, a protein found in hair
Problem 2a
Classify each of the following proteins according to its function:
a. insulin, a protein needed for glucose utilization
Problem 2c
Classify each of the following proteins according to its function:
c. casein, milk protein
Problem 4
How does the polarity of the R group in leucine compare to the R group in serine?
Problem 6a
Draw the structure for each of the following amino acids at physiological pH:
a. lysine
Problem 7
Classify each of the amino acids in problem 16.5 as polar or nonpolar. If polar, indicate if the R group is neutral, acidic, or basic. Indicate if each is hydrophobic or hydrophilic.
Problem 9d
Give the name for the amino acid represented by each of the following abbreviations:
d. Cys
Problem 10d
Give the name for the amino acid represented by each of the following abbreviations:
d. G
Problem 11a
Draw the condensed structural formula for each of the following peptides, and give its three-letter and one-letter abbreviations:
a. alanylcysteine
Problem 11c
Draw the condensed structural formula for each of the following peptides, and give its three-letter and one-letter abbreviations:
c. glycylalanylvaline
Problem 12b
Draw the condensed structural formula for each of the following peptides, and give its three-letter and one-letter abbreviations:
b. threonylleucine
Problem 12d
Draw the condensed structural formula for each of the following peptides, and give its three-letter and one-letter abbreviations:
d. histidylglycylglutamylisoleucine
Problem 13a
Peptides isolated from rapeseed that may lower blood pressure have the following sequence of amino acids. Draw the structure for each peptide and write the one-letter abbreviations.
a. Arg–Ile–Tyr
Problem 14b
Peptides from sweet potato with antioxidant properties have the following sequence of amino acids. Draw the structure for each peptide and write the one-letter abbreviations.
b. Asn–Tyr–Asp–Glu–Tyr
Problem 16a
Explain why each of the following pairs are complementary proteins:
a. beans and oats
Problem 17
What happens when a primary structure forms a secondary structure?
Problem 19
What is the difference in hydrogen bonding between an α helix and a β−pleated sheet?
Problem 21c
What type of interaction would you expect between the R groups of the following amino acids in a tertiary structure?
c. serine and aspartate
Problem 22a
What type of interaction would you expect between the R groups of the following amino acids in a quaternary structure?
a. phenylalanine and isoleucine
Problem 22d
What type of interaction would you expect between the R groups of the following amino acids in a quaternary structure?
d. alanine and proline
Problem 23a
A portion of a polypeptide chain contains the following sequence of amino acids:
—Leu—Val—Cys—Asp—
a. Which amino acids are likely to be found on the inside of the protein structure? Why?
Problem 23c
A portion of a polypeptide chain contains the following sequence of amino acids:
—Leu—Val—Cys—Asp—
c. How does the primary structure of a protein affect its tertiary structure?
Problem 24a
In myoglobin, about one-half of the 153 amino acids have nonpolar R groups.
a. Where would you expect those amino acids to be located in the tertiary structure?