Question 1

Adult hemoglobin is half saturated with oxygen at what partial pressure of oxygen?

Accepted Answer

A)   5 torr
B)   10 torr
C)   25 torr
D)   50 torr
E)   100 torrF) B) and D)
G) B) and C)

Question 2

Which of the following is often found connecting the strands of an antiparallel β-sheet?

Accepted Answer

A)   β-bulge
B)   reverse turn
C)   α-helix
D)   prosthetic groupE) A) and C)
F) B) and C)

Question 3

Heme would best be described as a

Accepted Answer

A)   motif.
B)   domain.
C)   prosthetic group.
D)   helix.E) A) and B)
F) A) and C)

Question 4

Which of the following statements regarding hemoglobin (Hb)  and myoglobin (Mb)  is true?

Accepted Answer

A)   Mb transports oxygen while Hb stores it.
B)   Mb has quaternary structure but Hb does not.
C)   Mb displays simple kinetics of binding while Hb displays cooperativity.
D)   Mb binds Fe(II)  while Hb binds heme.E) A) and D)
F) None of the above

Question 5

Exhibit 4B
 
-Refer to Exhibit 4B. The type of bonding labeled "N" 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 attractionF) A) and C)
G) A) and E)

Question 6

Exhibit 4B
 
-Refer to Exhibit 4B. Which one shows hydrogen bonding of the peptide backbone?

Accepted Answer

A)   M
B)   N
C)   P
D)   M and N
E)   All of theseF) None of the above
G) A) and E)

Question 7

The following bond forces are important in tertiary 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 tertiary structureF) A) and B)
G) D) and E)

Question 8

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 theseE) None of the above
F) C) and D)

Question 9

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 unchangedE) A) and B)
F) All of the above

Question 10

Hemoglobin differs from myoglobin because

Accepted Answer

A)   it does not have a heme group.
B)   it is a tetramer, whereas myoglobin is a single polypeptide chain.
C)   it does not contain any helical regions.
D)   it contains more β-pleated sheet structure.E) C) and D)
F) B) and D)

Question 11

Domains are

Accepted Answer

A)   independently folded regions of proteins
B)   the α-helical portions of proteins
C)   the β-pleated regions of proteins
D)   all of the aboveE) A) and B)
F) A) and D)

Question 12

Which one is not an example of supersecondary structure?

Accepted Answer

A)   the pyrrole ring
B)   the Greek key
C)   the β-meander
D)   the β-barrelE) C) and D)
F) B) and C)

Question 13

The location of prosthetic groups is shown in this level of structure:

Accepted Answer

A)   primary structure
B)   secondary structure
C)   tertiary structure
D)   quaternary structure
E)   All of theseF) B) and D)
G) C) and E)

Question 14

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 theseF) All of the above
G) A) and E)

Question 15

Which of the following amino acids is unlikely to be found in an α-helix?

Accepted Answer

A)   phenylalanine
B)   tryptophan
C)   proline
D)   lysineE) None of the above
F) C) and D)

Question 16

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)   methionineE) A) and B)
F) A) and C)

Question 17

In what oxidation state must the iron atom be for heme to bind oxygen?

Accepted Answer

A)   0, Fe(0) 
B)   1+, Fe(I) 
C)   2+, Fe(II) 
D)   3+, Fe(III) 
E)   There is no required oxidation state for the iron.F) A) and B)
G) All of the above

Question 18

Assuming the oligopeptide ALPHAHELICKS forms one continuous α-helix, the carbonyl oxygen of the glutamic acid residue is hydrogen bonded to the amide nitrogen of

Accepted Answer

A)   leucine.
B)   isoleucine.
C)   cysteine.
D)   lysine.
E)   serine.F) A) and C)
G) C) and D)

Question 19

Which of the following can result in protein denaturation?

Accepted Answer

A)   heat
B)   extremes of pH
C)   detergents
D)   all of the aboveE) All of the above
F) C) and D)

Question 20

Proteins that aid in the correct and timely folding of other proteins are called

Accepted Answer

A)   motifs.
B)   chaperones.
C)   liposomes.
D)   cooperative.E) All of the above
F) B) and C)

Exam 4: The Three-Dimensional Structure of Proteins

In what oxidation state must the iron atom be for heme to bind oxygen?

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Which of the following statements regarding hemoglobin (Hb) and myoglobin (Mb) is true?

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Which of the following amino acids is unlikely to be found in an α-helix?

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Which one is not an example of supersecondary structure?

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Exhibit 4B -Refer to Exhibit 4B. Which one shows hydrogen bonding of the peptide backbone?

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X-ray crystallography is used to determine protein structure because

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Proteins that aid in the correct and timely folding of other proteins are called

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

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Which of the following can result in protein denaturation?

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Which of the following is often found connecting the strands of an antiparallel β-sheet?

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The following bond forces are important in tertiary structure:

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Adult hemoglobin is half saturated with oxygen at what partial pressure of oxygen?

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The location of prosthetic groups is shown in this level of structure:

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

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Heme would best be described as a

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In the Bohr effect the binding of oxygen to hemoglobin

Correct AnswerverifiedShow Answer

Assuming the oligopeptide ALPHAHELICKS forms one continuous α-helix, the carbonyl oxygen of the glutamic acid residue is hydrogen bonded to the amide nitrogen of

Correct AnswerverifiedShow Answer

Hemoglobin differs from myoglobin because

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Domains are

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

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