Question 1

Why are glycine and proline often found within a $\beta$ turn?

Accepted Answer

A <img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30"> turn results in a tight 180° reversal...

Question 2

A repeating structural unit in a multimeric protein is known as a(n) :

Accepted Answer

A)  domain.
B)  motif.
C)  oligomer.
D)  protomer.
E)  subunit.

Question 3

Draw the resonance structure of a peptide bond,and explain why there is no rotation around the C-N bond.

Accepted Answer

The intermediate resonance str...

Question 4

Name four factors (bonds or other forces)that contribute to stabilizing the native structure of a protein,and describe one condition or reagent that interferes with each type of stabilizing force.

Accepted Answer

Any of the following forces stabilize na...

Question 5

Explain how circular dichroism spectroscopy could be used to measure the denaturation of a protein.

Accepted Answer

Circular dichroism spectroscopy measures...

Question 6

Proteostasis is the cellular process by which:

Accepted Answer

A)  proteins are synthesized.
B)  proteins are folded.
C)  proteins are modified.
D)  proteins are degraded.
E)  protein levels are maintained.

Question 7

Provide a brief explanation for the statement "Soluble globular proteins can be distinguished from soluble intrinsically disordered proteins on the basis of their amino acid content."

Accepted Answer

Soluble globular proteins contain signif...

Question 8

The structural classification of proteins (based on motifs) is based primarily on their:

Accepted Answer

A)  amino-acid sequence.
B)  evolutionary relationships.
C)  function.
D)  secondary structure content and arrangement.
E)  subunit content and arrangement.

Question 9

All of the following are considered "weak" interactions in proteins except:

Accepted Answer

A)  hydrogen bonds.
B)  hydrophobic interactions.
C)  ionic bonds.
D)  peptide bonds.
E)  van der Waals forces.

Question 10

Which of the following statements is false?

Accepted Answer

A)  Collagen is a protein in which the polypeptides are mainly in the  α\alphaα -helix conformation.
B)  Disulfide linkages are important for keratin structure.
C)  Gly residues are particularly abundant in collagen.
D)  Silk fibroin is a protein in which the polypeptide is almost entirely in the  β\betaβ  conformation.
E)  ( α\alphaα -keratin is a protein in which the polypeptides are mainly in the  α\alphaα 0-helix conformation.)

Question 11

Roughly how many amino acids are there in one turn of an  α\alphaα helix?

Accepted Answer

A)  1
B)  2) 8
C)  3) 6
D)  4) 2
E)  10

Question 12

Protein S will fold into its native conformation only when protein Q is also present in the solution.However,protein Q can fold into its native conformation without protein S.Protein Q,therefore,may function as a ____________ for protein S.

Accepted Answer

A)  proteasome
B)  molecular chaperone
C)  protein precursor
D)  structural motif
E)  supersecondary structural unit

Question 13

In the diagram below,the plane drawn behind the peptide bond indicates the:  \alpha  -N bond. C) region of steric hindrance determined by the large C=O group. D) region of the peptide bond that contributes to a Ramachandran plot. E) theoretical space between -180 and +180 degrees that can be occupied by the  \phi  and  \Psi  angles in the peptide bond. " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  absence of rotation around the C-N bond because of its partial double-bond character.
B)  plane of rotation around the C  α\alphaα  -N bond.
C)  region of steric hindrance determined by the large C=O group.
D)  region of the peptide bond that contributes to a Ramachandran plot.
E)  theoretical space between -180 and +180 degrees that can be occupied by the  ϕ\phiϕ  and  Ψ\PsiΨ  angles in the peptide bond.

Question 14

The three-dimensional conformation of a protein may be strongly influenced by amino acid residues that are very far apart in sequence.This relationship is in contrast to secondary structure,where the amino acid residues are:

Accepted Answer

A)  always side by side.
B)  generally near each other in sequence.
C)  invariably restricted to about 7 of the 20 standard amino acids.
D)  often on different polypeptide strands.
E)  usually near the polypeptide chain's amino terminus or carboxyl terminus.

Question 15

In an  α\alphaα  helix,the R groups on the amino acid residues:

Accepted Answer

A)  alternate between the outside and the inside of the helix.
B)  are found on the outside of the helix spiral.
C)  cause only right-handed helices to form.
D)  generate the hydrogen bonds that form the helix.
E)  stack within the interior of the helix.

Question 16

Which of the following pairs of bonds within a peptide backbone show free rotation around both bonds?

Accepted Answer

A)  C  α\alphaα  -C and N-C  α\alphaα  
B)  C=O and N-C
C)  C=O and N-C  α\alphaα  
D)  N-C and C  α\alphaα  -C
E)  N-C  α\alphaα   and N-C

Question 17

Proteins are classified within families or superfamilies based on similarities in:

Accepted Answer

A)  evolutionary origin.
B)  physico-chemical properties.
C)  structure and/or function.
D)  subcellular location.
E)  subunit structure.

Question 18

Explain what is meant by motifs in protein structure.

Accepted Answer

Motifs are particularly stable...

Question 19

Which of the following is not known to be involved in the process of assisted folding of proteins?

Accepted Answer

A)  Chaperonins
B)  Disulfide interchange
C)  Heat shock proteins
D)  Peptide bond condensation
E)  Peptide bond isomerization

Question 20

Describe the quaternary structure of hemoglobin.

Accepted Answer

Each protein molecule is compo...

Exam 4: The Three-Dimensional Structure of Proteins

In an $\alpha$ helix,the R groups on the amino acid residues:

Correct Answer
verified

All of the following are considered "weak" interactions in proteins except:

Correct Answer
verified

Explain how circular dichroism spectroscopy could be used to measure the denaturation of a protein.

Correct Answer
verified
Circular dichroism spectroscopy measures...
View Answer

Name four factors (bonds or other forces)that contribute to stabilizing the native structure of a protein,and describe one condition or reagent that interferes with each type of stabilizing force.

Correct Answer
verified
Any of the following forces stabilize na...
View Answer

Which of the following is not known to be involved in the process of assisted folding of proteins?

Correct Answer
verified

Which of the following pairs of bonds within a peptide backbone show free rotation around both bonds?

Correct Answer
verified

Why are glycine and proline often found within a $\beta$ turn?

Correct Answer
verified
A turn results in a tight 180° reversal...
View Answer

Draw the resonance structure of a peptide bond,and explain why there is no rotation around the C-N bond.

Correct Answer
verified
The intermediate resonance str...
View Answer

Describe the quaternary structure of hemoglobin.

Correct Answer
verified
Each protein molecule is compo...
View Answer

A repeating structural unit in a multimeric protein is known as a(n) :

Correct Answer
verified

The three-dimensional conformation of a protein may be strongly influenced by amino acid residues that are very far apart in sequence.This relationship is in contrast to secondary structure,where the amino acid residues are:

Correct Answer
verified

Proteins are classified within families or superfamilies based on similarities in:

Correct Answer
verified

Proteostasis is the cellular process by which:

Correct Answer
verified

Protein S will fold into its native conformation only when protein Q is also present in the solution.However,protein Q can fold into its native conformation without protein S.Protein Q,therefore,may function as a ____________ for protein S.

Correct Answer
verified

Explain what is meant by motifs in protein structure.

Correct Answer
verified
Motifs are particularly stable...
View Answer

Provide a brief explanation for the statement "Soluble globular proteins can be distinguished from soluble intrinsically disordered proteins on the basis of their amino acid content."

Correct Answer
verified
Soluble globular proteins contain signif...
View Answer

Which of the following statements is false?

Correct Answer
verified

Correct Answer
verified

The structural classification of proteins (based on motifs) is based primarily on their:

Correct Answer
verified

Roughly how many amino acids are there in one turn of an $\alpha$ helix?

Correct Answer
verified

Exam 4: The Three-Dimensional Structure of Proteins

In an α\alphaα helix,the R groups on the amino acid residues:

Correct AnswerverifiedShow Answer

All of the following are considered "weak" interactions in proteins except:

Correct AnswerverifiedShow Answer

Explain how circular dichroism spectroscopy could be used to measure the denaturation of a protein.

Correct AnswerverifiedCircular dichroism spectroscopy measures...View AnswerShow Answer

Name four factors (bonds or other forces)that contribute to stabilizing the native structure of a protein,and describe one condition or reagent that interferes with each type of stabilizing force.

Correct AnswerverifiedAny of the following forces stabilize na...View AnswerShow Answer

Which of the following is not known to be involved in the process of assisted folding of proteins?

Correct AnswerverifiedShow Answer

Which of the following pairs of bonds within a peptide backbone show free rotation around both bonds?

Correct AnswerverifiedShow Answer

Why are glycine and proline often found within a β\betaβ turn?

Correct AnswerverifiedA turn results in a tight 180° reversal...View AnswerShow Answer

Draw the resonance structure of a peptide bond,and explain why there is no rotation around the C-N bond.

Correct AnswerverifiedThe intermediate resonance str...View AnswerShow Answer

Describe the quaternary structure of hemoglobin.

Correct AnswerverifiedEach protein molecule is compo...View AnswerShow Answer

A repeating structural unit in a multimeric protein is known as a(n) :

Correct AnswerverifiedShow Answer

The three-dimensional conformation of a protein may be strongly influenced by amino acid residues that are very far apart in sequence.This relationship is in contrast to secondary structure,where the amino acid residues are:

Correct AnswerverifiedShow Answer

Proteins are classified within families or superfamilies based on similarities in:

Correct AnswerverifiedShow Answer

Proteostasis is the cellular process by which:

Correct AnswerverifiedShow Answer

Protein S will fold into its native conformation only when protein Q is also present in the solution.However,protein Q can fold into its native conformation without protein S.Protein Q,therefore,may function as a ____________ for protein S.

Correct AnswerverifiedShow Answer

Explain what is meant by motifs in protein structure.

Correct AnswerverifiedMotifs are particularly stable...View AnswerShow Answer

Provide a brief explanation for the statement "Soluble globular proteins can be distinguished from soluble intrinsically disordered proteins on the basis of their amino acid content."

Correct AnswerverifiedSoluble globular proteins contain signif...View AnswerShow Answer

Which of the following statements is false?

Correct AnswerverifiedShow Answer

In the diagram below,the plane drawn behind the peptide bond indicates the:

Correct AnswerverifiedShow Answer

The structural classification of proteins (based on motifs) is based primarily on their:

Correct AnswerverifiedShow Answer

Roughly how many amino acids are there in one turn of an α\alphaα helix?

Correct AnswerverifiedShow Answer

In an $\alpha$ helix,the R groups on the amino acid residues:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Circular dichroism spectroscopy measures...
View Answer

Correct Answer
verified
Any of the following forces stabilize na...
View Answer

Correct Answer
verified

Correct Answer
verified

Why are glycine and proline often found within a $\beta$ turn?

Correct Answer
verified
A turn results in a tight 180° reversal...
View Answer

Correct Answer
verified
The intermediate resonance str...
View Answer

Correct Answer
verified
Each protein molecule is compo...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Motifs are particularly stable...
View Answer

Correct Answer
verified
Soluble globular proteins contain signif...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Roughly how many amino acids are there in one turn of an $\alpha$ helix?

Correct Answer
verified