Question 1

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 2

Which of the following is true about the alpha helix?

Accepted Answer

A)  the structure is stablized by hydrogen bonds 
B)  there are 3.6 residues for every turn of the helix 
C)  the pitch of the helix is 5.4 angsroms 
D)  all of the choices 
A)  the structure is stablized by hydrogen bonds 
B)  there are 3.6 residues for every turn of the helix 
C)  the pitch of the helix is 5.4 angsroms 
D)  all of the choices

Question 3

In the β-pleated sheet conformation

Accepted Answer

A)  there are hydrogen bonds perpendicular to the direction of the polypeptide chain. 
B)  the polypeptide chain is almost fully extended. 
C)  the polypeptide chains may be hydrogen bonded together in a parallel or antiparallel orientation. 
D)  all of these 
A)  there are hydrogen bonds perpendicular to the direction of the polypeptide chain. 
B)  the polypeptide chain is almost fully extended. 
C)  the polypeptide chains may be hydrogen bonded together in a parallel or antiparallel orientation. 
D)  all of these

Question 4

Which of the following diseases is based on abnormal protein folding?

Accepted Answer

A)  Alzheimers disease 
B)  Mad Cow Disease 
C)  Prion diseases 
D)  Frontotemporal dementia 
E)  All of the choices 
A)  Alzheimers disease 
B)  Mad Cow Disease 
C)  Prion diseases 
D)  Frontotemporal dementia 
E)  All of the choices

Question 5

Which of the following best describes a motif?

Accepted Answer

A)  a repetitive supersecondary structure 
B)  a common nonrepetitive irregularity found in antiparallel β-sheets 
C)  a protein conformation with biological activity 
D)  a group of atoms other than an amino acid 
A)  a repetitive supersecondary structure 
B)  a common nonrepetitive irregularity found in antiparallel β-sheets 
C)  a protein conformation with biological activity 
D)  a group of atoms other than an amino acid

Question 6

Under normal circumstances:

Accepted Answer

A)  Adult Hb binds to oxygen more tightly than Mb binds. 
B)  Fetal Hb binds oxygen more tightly than adult Hb. 
C)  Adult Hb binds oxygen more tightly than either fetal Hb or Mb binds. 
D)  Mb has the lowest affinity for oxygen of the 3. 
E)  More than one of these statements is correct. 
A)  Adult Hb binds to oxygen more tightly than Mb binds. 
B)  Fetal Hb binds oxygen more tightly than adult Hb. 
C)  Adult Hb binds oxygen more tightly than either fetal Hb or Mb binds. 
D)  Mb has the lowest affinity for oxygen of the 3. 
E)  More than one of these statements is correct.

Question 7

As an animal ages, the amount of cross-linking of collagen in tissue

Accepted Answer

A)  tends to decrease. 
B)  tends to increase. 
C)  tends to remain unchanged. 
A)  tends to decrease. 
B)  tends to increase. 
C)  tends to remain unchanged.

Question 8

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 9

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

Question 10

Which of the following is true?

Accepted Answer

A)  The peptide bonds in the β-sheet are extended. 
B)  The peptide bonds in the α-helix coil back on themselves. 
C)  Both α-helices and β-sheets can be found as part of tertiary structure. 
D)  All of these 
A)  The peptide bonds in the β-sheet are extended. 
B)  The peptide bonds in the α-helix coil back on themselves. 
C)  Both α-helices and β-sheets can be found as part of tertiary structure. 
D)  All of these

Question 11

The structure of myoglobin consists

Accepted Answer

A)  almost entirely of α-helices. 
B)  almost entirely of β-sheets. 
C)  of a mixture of α-helices and β-sheets. 
D)  of a unique secondary motif that is neither α-helix nor β-sheet. 
A)  almost entirely of α-helices. 
B)  almost entirely of β-sheets. 
C)  of a mixture of α-helices and β-sheets. 
D)  of a unique secondary motif that is neither α-helix nor β-sheet.

Question 12

Variations in the structure of hemoglobin

Accepted Answer

A)  do not always have an adverse effect on health 
B)  can alter the binding of heme to the protein 
C)  can occur on the surface of the protein 
D)  all of these 
A)  do not always have an adverse effect on health 
B)  can alter the binding of heme to the protein 
C)  can occur on the surface of the protein 
D)  all of these

Question 13

Incorrect protein folding resulting in exposure of hydrophobic regions can result in

Accepted Answer

A)  aggregation. 
B)  homology. 
C)  liposomes. 
D)  the Bohr effect. 
A)  aggregation. 
B)  homology. 
C)  liposomes. 
D)  the Bohr effect.

Question 14

A single amino substitution can give rise to a malfunctioning protein.

Accepted Answer

A) True 
 B)False

Question 15

Which of the following statements regarding hydrogen bonding in secondary structures is true?

Accepted Answer

A)  Both α-helices and β-sheets only use intrachain hydrogen bonds. 
B)  Both α-helices and β-sheets only use interchain hydrogen bonds. 
C)  α-helices only use intrachain hydrogen bonds and β-sheets can use either intrachain or interchain hydrogen bonds. 
D)  α-helices can use either intrachain or interchain hydrogen bonds and β-sheets only use interchain hydrogen bonds. 
A)  Both α-helices and β-sheets only use intrachain hydrogen bonds. 
B)  Both α-helices and β-sheets only use interchain hydrogen bonds. 
C)  α-helices only use intrachain hydrogen bonds and β-sheets can use either intrachain or interchain hydrogen bonds. 
D)  α-helices can use either intrachain or interchain hydrogen bonds and β-sheets only use interchain hydrogen bonds.

Question 16

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 17

Hydroxyurea works as a treatment for sickle cell anemia because it

Accepted Answer

A)  causes myoglobin to act like hemoglobin 
B)  causes the body to produce fetal hemoglobin 
C)  causes hemoglobin to dissociate into monomers, thereby quadrupline the effective concentration of oxygen carrying molecules 
D)  none of the choices 
A)  causes myoglobin to act like hemoglobin 
B)  causes the body to produce fetal hemoglobin 
C)  causes hemoglobin to dissociate into monomers, thereby quadrupline the effective concentration of oxygen carrying molecules 
D)  none of the choices

Question 18

Which of the following is true about sickle cell hemoglobin?

Accepted Answer

A)  it has a single amino acid substitution in the beta chain 
B)  it causes a disease that is always fatal 
C)  it is found as a monomer instead of a tetramer in red blood cells 
D)  it has a leucine at a position where normal hemoglobin has an isoleucine 
E)  none of the choices 
A)  it has a single amino acid substitution in the beta chain 
B)  it causes a disease that is always fatal 
C)  it is found as a monomer instead of a tetramer in red blood cells 
D)  it has a leucine at a position where normal hemoglobin has an isoleucine 
E)  none of the choices

Question 19

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 20

Which of the following factors tend to destabilize α-helices?

Accepted Answer

A)  clusters of amino acids with bulky R-groups 
B)  clusters of amino acids with similarly charged R-groups 
C)  Both of these. 
D)  Neither of these 
A)  clusters of amino acids with bulky R-groups 
B)  clusters of amino acids with similarly charged R-groups 
C)  Both of these. 
D)  Neither of these

Exam 4: The Three-Dimensional Structure of Proteins

Two amino acids frequently found in reverse turns are

Which of the following is true about the alpha helix?

In the β-pleated sheet conformation

Which of the following diseases is based on abnormal protein folding?

Which of the following best describes a motif?

Under normal circumstances:

As an animal ages, the amount of cross-linking of collagen in tissue

Which of the following best describes the structure of collagen?

Quaternary structure is associated with

Which of the following is true?

The structure of myoglobin consists

Variations in the structure of hemoglobin

Incorrect protein folding resulting in exposure of hydrophobic regions can result in

A single amino substitution can give rise to a malfunctioning protein.

Which of the following statements regarding hydrogen bonding in secondary structures is true?

In the α-helix

Hydroxyurea works as a treatment for sickle cell anemia because it

Which of the following is true about sickle cell hemoglobin?

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

Which of the following factors tend to destabilize α-helices?

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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