Question 1

Quaternary structure is associated with

Accepted Answer

A)  the overall shape of the polypeptide chain 
B)  the sum of secondary and tertiary interactions 
C)  simple proteins with only one subunit 
D)  the relative orientation of one polypeptide to another polypeptide in a multisubunit protein 
A)  the overall shape of the polypeptide chain 
B)  the sum of secondary and tertiary interactions 
C)  simple proteins with only one subunit 
D)  the relative orientation of one polypeptide to another polypeptide in a multisubunit protein D

Question 2

The information needed for the structure of a protein is contained in

Accepted Answer

A)  amino acid composition 
B)  primary structure 
C)  secondary structure 
D)  tertiary structure 
A)  amino acid composition 
B)  primary structure 
C)  secondary structure 
D)  tertiary structure B

Question 3

In the Bohr effect the binding of oxygen to hemoglobin

Accepted Answer

A)  is increased by the presence of Na+ 
B)  is increased by the presence of H+ and CO2 
C)  is decreased by the presence of H+ and CO2 
D)  is unchanged 
A)  is increased by the presence of Na+ 
B)  is increased by the presence of H+ and CO2 
C)  is decreased by the presence of H+ and CO2 
D)  is unchanged C

Question 4

Exhibit 4B   Refer to Exhibit 4B. Which one shows electrostatic attraction of R-groups?

Accepted Answer

A)  K 
B)  L 
C)  O 
D)  K and L 
E)  All of these 
A)  K 
B)  L 
C)  O 
D)  K and L 
E)  All of these

Question 5

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 6

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 7

Structures which repeat over and over in secondary structure are called:

Accepted Answer

A)  primary structure 
B)  domain 
C)  supersecondary structure 
D)  prosthetic group 
E)  All of these 
A)  primary structure 
B)  domain 
C)  supersecondary structure 
D)  prosthetic group 
E)  All of these

Question 8

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 9

X-ray crystallography is used to determine protein structure because

Accepted Answer

A)  it can be done on dilute solutions 
B)  it requires no calculations 
C)  the positions of all atoms can be found by this method 
D)  all of these 
A)  it can be done on dilute solutions 
B)  it requires no calculations 
C)  the positions of all atoms can be found by this method 
D)  all of these

Question 10

Why does myoglobin have a histidine that prevents both O2 and CO from binding perpendicularly to the heme plane?

Accepted Answer

A)  This increases myoglobin's affinity for O2. 
B)  This increases myoglobin's affinity for CO. 
C)  This lessens the difference in myoglobin's affinity for CO versus O2. 
D)  This prevents the iron of the heme from being oxidized. 
A)  This increases myoglobin's affinity for O2. 
B)  This increases myoglobin's affinity for CO. 
C)  This lessens the difference in myoglobin's affinity for CO versus O2. 
D)  This prevents the iron of the heme from being oxidized.

Question 11

Two amino acids frequently found in reverse turns are

Accepted Answer

A)  tyrosine and tryptophan 
B)  serine and threonine 
C)  glycine and proline 
D)  leucine and isoleucine 
A)  tyrosine and tryptophan 
B)  serine and threonine 
C)  glycine and proline 
D)  leucine and isoleucine

Question 12

In the α -helix

Accepted Answer

A)  there are no hydrogen bonds 
B)  the peptide chain is fully extended 
C)  the peptide chain bends back on itself 
D)  there are hydrogen bonds parallel to the helix axis 
A)  there are no hydrogen bonds 
B)  the peptide chain is fully extended 
C)  the peptide chain bends back on itself 
D)  there are hydrogen bonds parallel to the helix axis

Question 13

Disulfide bonds in proteins occur between the side chains of which of the following amino acid residues?

Accepted Answer

A)  glutamine 
B)  lysine 
C)  cysteine 
D)  methionine 
A)  glutamine 
B)  lysine 
C)  cysteine 
D)  methionine

Question 14

Which of the following best describes the structure of collagen?

Accepted Answer

A)  It is composed of a single α -helix. 
B)  It is a double helix. 
C)  It is a triple helix 
D)  It is composed primarily of β -sheet. 
A)  It is composed of a single α -helix. 
B)  It is a double helix. 
C)  It is a triple helix 
D)  It is composed primarily of β -sheet.

Question 15

What would happen to hemoglobin if the BPG were removed?

Accepted Answer

A)  It would not bind oxygen 
B)  It would dissociate into monomers 
C)  its oxygen binding curve would resemble that of myoglobin 
D)  all of the choices 
A)  It would not bind oxygen 
B)  It would dissociate into monomers 
C)  its oxygen binding curve would resemble that of myoglobin 
D)  all of the choices

Question 16

What is the major force that drives nonpolar substances out of aqueous solution?

Accepted Answer

A)  Increased enthalpy of hydrophobic bonds formed between solute molecules. 
B)  Decreased entropy of newly organized solute molecules. 
C)  Increased entropy of newly organized solute molecules. 
D)  Increased enthalpy of H-bonds in the solvent water. 
E)  Increased entropy of solvent water molecules. 
A)  Increased enthalpy of hydrophobic bonds formed between solute molecules. 
B)  Decreased entropy of newly organized solute molecules. 
C)  Increased entropy of newly organized solute molecules. 
D)  Increased enthalpy of H-bonds in the solvent water. 
E)  Increased entropy of solvent water molecules.

Question 17

The overall folding of a single protein subunit is called:

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 18

Which of the following amino acid residues would most likely be found in the interior of a globular protein?

Accepted Answer

A)  glutamic acid 
B)  lysine 
C)  leucine 
D)  serine 
A)  glutamic acid 
B)  lysine 
C)  leucine 
D)  serine

Question 19

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 20

Exhibit 4A The following question(s) refer to this peptide:
Cys-Ala-Gly-Arg-Gln-Met
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

Exam 4: The Three Dimensional Structure of Proteins

Quaternary structure is associated with

The information needed for the structure of a protein is contained in

In the Bohr effect the binding of oxygen to hemoglobin

Exhibit 4B Refer to Exhibit 4B. Which one shows electrostatic attraction of R-groups?

Which of the following is not true?

Which of the following is not a characteristic of hemoglobin?

Structures which repeat over and over in secondary structure are called:

Which of the following is true?

X-ray crystallography is used to determine protein structure because

Why does myoglobin have a histidine that prevents both O2 and CO from binding perpendicularly to the heme plane?

Two amino acids frequently found in reverse turns are

In the α -helix

Disulfide bonds in proteins occur between the side chains of which of the following amino acid residues?

Which of the following best describes the structure of collagen?

What would happen to hemoglobin if the BPG were removed?

What is the major force that drives nonpolar substances out of aqueous solution?

The overall folding of a single protein subunit is called:

Which of the following amino acid residues would most likely be found in the interior of a globular protein?

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

Exhibit 4A The following question(s) refer to this peptide: Cys-Ala-Gly-Arg-Gln-Met Refer to Exhibit 4A. The overall, net ionic charge on this peptide at pH = 7 would be:

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 the 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

Filters

Why does myoglobin have a histidine that prevents both O₂ and CO from binding perpendicularly to the heme plane?