Question 1

What happens when a protein is denatured?

Accepted Answer

A)  Its secondary structure is disrupted but its primary structure remains intact. 
B)  Its primary structure is disrupted but its secondary structure remains intact. 
C)  It is broken apart into its constituent amino acids. 
D)  It becomes all α-helix. 
A)  Its secondary structure is disrupted but its primary structure remains intact. 
B)  Its primary structure is disrupted but its secondary structure remains intact. 
C)  It is broken apart into its constituent amino acids. 
D)  It becomes all α-helix.

Question 2

Hydrogen bonds are most important in this type of structure in proteins:

Accepted Answer

A)  primary structure 
B)  secondary structure 
C)  tertiary structure 
D)  quaternary structure 
E)  All of these 
A)  primary structure 
B)  secondary structure 
C)  tertiary structure 
D)  quaternary structure 
E)  All of these

Question 3

Which of the following forces are involved in maintaining the quaternary structure of a protein?

Accepted Answer

A)  hydrogen bonds 
B)  ionic interactions 
C)  hydrophobic interactions 
D)  All of these 
A)  hydrogen bonds 
B)  ionic interactions 
C)  hydrophobic interactions 
D)  All of these

Question 4

Which of the following is not a characteristic of hemoglobin?

Accepted Answer

A)  It contains two different types of subunits . 
B)  It contains a prosthetic group. 
C)  It is an allosteric enzyme. 
D)  It transports oxygen. 
E)  All of these statements are true for Hb. 
A)  It contains two different types of subunits . 
B)  It contains a prosthetic group. 
C)  It is an allosteric enzyme. 
D)  It transports oxygen. 
E)  All of these statements are true for Hb.

Question 5

Refer to Exhibit 4A. The overall, net ionic charge on this peptide at pH = 7 would be:

Accepted Answer

A)  +2 
B)  +1 
C)  0 
D)  −1 
E)  −2 
A)  +2 
B)  +1 
C)  0 
D)  −1 
E)  −2

Question 6

Disulfide bonds are most important in this type of structure:

Accepted Answer

A)  primary structure 
B)  secondary structure 
C)  tertiary structure 
D)  quaternary structure 
E)  All of these 
A)  primary structure 
B)  secondary structure 
C)  tertiary structure 
D)  quaternary structure 
E)  All of these

Question 7

Which of the following amino acid substitutions would be least likely to have a deleterious effect on protein function?

Accepted Answer

A)  His changes to Asp 
B)  Leu changes to Ile 
C)  Glu changes to Gln 
D)  Trp changes to Gly 
A)  His changes to Asp 
B)  Leu changes to Ile 
C)  Glu changes to Gln 
D)  Trp changes to Gly

Question 8

Which of the following best defines a domain?

Accepted Answer

A)  A supersecondary region, often shared by proteins, that has a specific function. 
B)  A repetitive supersecondary structure. 
C)  A double-layered arrangement formed so that the polar groups face the aqueous environment, while the nonpolar regions are kept away from the aqueous environment. 
D)  An unfolded region of a protein. 
A)  A supersecondary region, often shared by proteins, that has a specific function. 
B)  A repetitive supersecondary structure. 
C)  A double-layered arrangement formed so that the polar groups face the aqueous environment, while the nonpolar regions are kept away from the aqueous environment. 
D)  An unfolded region of a protein.

Question 9

Exhibit 4B
  
-Refer to Exhibit 4B. The type of bonding labeled "O" in these figure is:

Accepted Answer

A)  Hydrogen bonding of the peptide backbone 
B)  Covalent bonding involving the R-groups 
C)  Hydrophobic interactions 
D)  Metal ion coordination 
E)  Electrostatic attraction 
A)  Hydrogen bonding of the peptide backbone 
B)  Covalent bonding involving the R-groups 
C)  Hydrophobic interactions 
D)  Metal ion coordination 
E)  Electrostatic attraction

Question 10

The following bond forces are important in quaternary structure:

Accepted Answer

A)  Disulfide bonds 
B)  Hydrogen bonds 
C)  Hydrophobic attraction 
D)  Both hydrogen bonds and hydrophobic attraction. 
E)  All of these are important in quaternary structure. 
A)  Disulfide bonds 
B)  Hydrogen bonds 
C)  Hydrophobic attraction 
D)  Both hydrogen bonds and hydrophobic attraction. 
E)  All of these are important in quaternary structure.

Question 11

Which of the following is not true?

Accepted Answer

A)  The heme group of myoglobin is held in place only through non-covalent bonding. 
B)  The F8 histidine is important to the function of myoglobin 
C)  The E7 histidine is important to the function of myoglobin 
D)  Myoglobin and hemoglobin differ only in one amino acid 
A)  The heme group of myoglobin is held in place only through non-covalent bonding. 
B)  The F8 histidine is important to the function of myoglobin 
C)  The E7 histidine is important to the function of myoglobin 
D)  Myoglobin and hemoglobin differ only in one amino acid

Question 12

The affinity of fetal hemoglobin for oxygen

Accepted Answer

A)  has not been studied 
B)  is the same as that of adult hemoglobin 
C)  is lower than that of maternal hemoglobin 
D)  is higher than that of maternal hemoglobin 
A)  has not been studied 
B)  is the same as that of adult hemoglobin 
C)  is lower than that of maternal hemoglobin 
D)  is higher than that of maternal hemoglobin

Question 13

Generally speaking, this type of protein is water-soluble:

Accepted Answer

A)  Fibrous. 
B)  Globular. 
C)  Both fibrous and globular proteins are usually water-soluble. 
D)  Neither fibrous nor globular proteins are usually water-soluble. 
E)  You cannot generalize about the solubility of fibrous or globular proteins. 
A)  Fibrous. 
B)  Globular. 
C)  Both fibrous and globular proteins are usually water-soluble. 
D)  Neither fibrous nor globular proteins are usually water-soluble. 
E)  You cannot generalize about the solubility of fibrous or globular proteins.

Question 14

Refer to Exhibit 4A. The amino terminal amino acid is:

Accepted Answer

A)  Arg 
B)  Cys 
C)  Gln 
D)  Met 
E)  None of these. 
A)  Arg 
B)  Cys 
C)  Gln 
D)  Met 
E)  None of these.

Question 15

The protein myoglobin

Accepted Answer

A)  contains a high degree of β-pleated sheet structure 
B)  carries oxygen in the bloodstream 
C)  contains no histidine 
D)  contains a heme group 
A)  contains a high degree of β-pleated sheet structure 
B)  carries oxygen in the bloodstream 
C)  contains no histidine 
D)  contains a heme group

Question 16

The following is true about the hydroxyproline in collagen:

Accepted Answer

A)  Hydroxyproline is incorporated into the chain during polymerization of amino acids. 
B)  Vitamin C is necessary for the synthesis of hydroxyproline. 
C)  Hydroxyproline is important in holding the 3 strands of collagen together. 
D)  Hydroxyproline requires Vitamin C for its synthesis and it holds the collagen helix together. 
E)  All of these. 
A)  Hydroxyproline is incorporated into the chain during polymerization of amino acids. 
B)  Vitamin C is necessary for the synthesis of hydroxyproline. 
C)  Hydroxyproline is important in holding the 3 strands of collagen together. 
D)  Hydroxyproline requires Vitamin C for its synthesis and it holds the collagen helix together. 
E)  All of these.

Question 17

The binding of oxygen to hemoglobin differs from the oxygen-binding behavior of myoglobin because

Accepted Answer

A)  oxygen binding to hemoglobin is cooperative. 
B)  oxygen binding to myoglobin is cooperative. 
C)  hemoglobin is not an allosteric protein. 
D)  the oxygen-binding curve of hemoglobin is hyperbolic. 
A)  oxygen binding to hemoglobin is cooperative. 
B)  oxygen binding to myoglobin is cooperative. 
C)  hemoglobin is not an allosteric protein. 
D)  the oxygen-binding curve of hemoglobin is hyperbolic.

Question 18

Which of the following is true?

Accepted Answer

A)  The collagen helix and the α-helix are the only types of helices in proteins. 
B)  Globular proteins tend to be water soluble 
C)  Globular and fibrous are examples of secondary structure 
D)  All of these 
A)  The collagen helix and the α-helix are the only types of helices in proteins. 
B)  Globular proteins tend to be water soluble 
C)  Globular and fibrous are examples of secondary structure 
D)  All of these

Question 19

The Bohr effect for oxygen binding states that

Accepted Answer

A)  Mb binds oxygen more tightly than Hb. 
B)  Hb will bind oxygen very tightly when the CO2 concentration is high. 
C)  as the pH goes down, Hb binds oxygen less tightly. 
D)  Hb's ability to bind oxygen increases with higher oxygen concentration. 
A)  Mb binds oxygen more tightly than Hb. 
B)  Hb will bind oxygen very tightly when the CO2 concentration is high. 
C)  as the pH goes down, Hb binds oxygen less tightly. 
D)  Hb's ability to bind oxygen increases with higher oxygen concentration.

Question 20

Covalent bonds are important in all these structures, except:

Accepted Answer

A)  primary structure 
B)  secondary structure 
C)  tertiary structure 
D)  quaternary structure 
E)  All of these 
A)  primary structure 
B)  secondary structure 
C)  tertiary structure 
D)  quaternary structure 
E)  All of these

Exam 4: The Three-Dimensional Structure of Proteins

What happens when a protein is denatured?

Hydrogen bonds are most important in this type of structure in proteins:

Which of the following forces are involved in maintaining the quaternary structure of a protein?

Which of the following is not a characteristic of hemoglobin?

Refer to Exhibit 4A. The overall, net ionic charge on this peptide at pH = 7 would be:

Disulfide bonds are most important in this type of structure:

Which of the following amino acid substitutions would be least likely to have a deleterious effect on protein function?

Which of the following best defines a domain?

Exhibit 4B -Refer to Exhibit 4B. The type of bonding labeled "O" in these figure is:

The following bond forces are important in quaternary structure:

Which of the following is not true?

The affinity of fetal hemoglobin for oxygen

Generally speaking, this type of protein is water-soluble:

Refer to Exhibit 4A. The amino terminal amino acid is:

The protein myoglobin

The following is true about the hydroxyproline in collagen:

The binding of oxygen to hemoglobin differs from the oxygen-binding behavior of myoglobin because

Which of the following is true?

The Bohr effect for oxygen binding states that

Covalent bonds are important in all these structures, except:

Biochemistry and the Organization of Cells

Water: the Solvent for Biochemical Reactions

Amino Acids and Peptides

Protein Purification and Characterization Techniques

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: Biosynthesis of RNA

Protein Synthesis: Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

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