Structure and Properties of Peptides
Content
1.
Hydrogen bonds in a-helices are
A
more numerous than Vander Waals interactions
.
B.not present at Phe residues
C.analogous to the steps in a spiral staircase
D
roughly parallel to the helix axis
.
2.
The peptide bond in proteins is
A
only found between proline residues
.
B.usually cis unless proline is the next amino acid
C.usually trans unless proline is the next amino acid
D
is planar because of steric hinderance
.
3.
The molecular formula for glycine is C2H5O2N. What would be the molecular formula for a linear oligomer
made by linking ten glycine molecules together by condensation synthesis?
A
C H O N
. 20 50 20 10
B.C20H32O11N10
C.C20H40O10N10
D
C H O N
. 20 68 29 10
4.
Which of the following is an example of tertiary structure in a protein?
A
A multimeric protein
.
B.An a-helix
C.A P-pleated sheet
D
A globular domain
.
5.
The peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with cyanogen bromide (CNBr) to produce:
A
Val-Lys + Glu-Met-Ser + Trp-Arg-Ala
.
B.Val-Lys-Glu-Met-Ser-Trp + Arg-Ala
C.Val-Lys-Glu-Met + Ser-Trp-Arg-Ala
D Val-Lys-Glu + Met-Ser-Trp-Arg-Ala
.
6.
In deoxy hemoglobin (Hb), the Fe (II) is coordinated to
A
four nitrogens of heme, the proximal His, and a water molecule
.
B.four nitrogens of heme and to a water molecule
C.two nitrogens of heme and to three His residues in Hb
D
two nitrogens of heme and to three water molecules
.
7.
In the β-pleated sheet
A
hydrogen bonds are formed between the peptide bonds
.
B.adjacent polypeptide chains can either be parallel or antiparallel
C.the polypeptide chain is fully extended
D
all of the above
.
8.
The Ramachandran Plot illustrates the fact that
A
the peptide bond is planar
.
B.the F & Y angles can assume any value in a peptide
C.the F & Y angles can assume only a single value in a protein
D
the F & Y angles can assume approximately three different values
.
9.
The resonance structures that can be drawn for the peptide bond indicate that the peptide bond
A
is stronger than an ordinary single bond
.
B.has partial double bond character
C.both (a) and (b)
D
is still not completely understood
.
10.
The major element of secondary structure in myoglobin and hemoglobin is
A
the P-strand
.
B.the a-helix
C.the reverse turn
D
All of these
.
11.
An oil drop with a polar coat is a metaphor referring to the three dimensional structure of
A
fibrous proteins
.
B.collagen
C.globular proteins
D
silk protein
.
Answer & Explanation
12.
What was the first protein whose complete tertiary structure was determined?
A
Lysozyme
.
B.Myoglobin
C.Pancreatic ribonuclease
D
Pancreatic DNase
.
13.
The peptide bond in proteins is
A
planar, but rotates to three preferred dihedral angles
.
B.nonpolar, but rotates to three preferred dihedral angles
C.nonpolar, and fixed in a trans conformation
D
planar, and usually found in a trans conformation
.
14.
In β-pleated sheet structures neighbouring
A
chains lie in a flat plane
.
B.neighboring residues are hydrogen bonded
C.neighboring chains are connected by a-helices
D
neighboring chains are hydrogen bonded
.
15.
The same peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala. was digested with chymotrypsin to produce
A
Val-Lys + Glu-Met-Ser + Trp-Arg-Ala.
.
B.Val-Lys-Glu-Met-Ser-Trp + Arg-Ala.
C.Val-Lys-Glu-Met-Ser + Trp-Arg-Ala.
D
Val-Lys-Glu-Met + Ser-Trp-Arg-Ala.
.
16.
Disulfide bonds most often stabilize the native structure of
A
extracellular proteins
.
B.dimeric proteins
C.hydrophobic proteins
D
intracellular proteins
.
Answer & Explanation
17.
Secondary structure in protein refers to
A
linear sequence of amino acids joined together by peptide bond
.
B.three dimensional arrangement of all amino acids in polypeptide chain
C.regular folding of regions of the polypeptide chain
D
protein made up of more than one polypeptide chain
.
18.
Heme is the binding pocket of myoglobin and hemoglobin and is composed of
A
negatively charged residues
.
B.polar residues
C.hydrophobic residues
D
positively charged residues
.
19.
What is the effect of a decrease in pH on hemoglobin oxygen affinity?
A
Decrease in oxygen affinity
.
B.Increase in oxygen affinity
C.No effect on oxygen affinity
D
Increase affinity in muscle cell otherwise decrease
.
Answer & Explanation
20.
What is the proportion of glycine residues in collagenous regions?
A
One-fourth
.
B.One-third
C.Half
D
One-tenth
.
21.
Which of the following statements is incorrect?
A
Protein G contains both a-helix and P-sheet
.
B.Protein G contains only a-helix
C.Fatty acid binding protein contains largely P-sheet
D
Hemoglobin contains four sub-units
.
22.
The oxygen binding curves of hemoglobin and myoglobin
A
allow maximum transfer of oxygen to the tissues
.
B.are a consequence of the quaternary structure of hemoglobin
C.both (a) and (b)
D
are identical
.
23.
The nature of peptide bond can be best explained as
A
partial double bond
.
B.truly double bond
C.Hydrogen bond
D
Van der waals force
.
24.
Which of the following statement is incorrect?
A
Hemoglobin and myoglobin are the two oxygen binding proteins
.
B.Hemoglobin transports O2 in the blood
C.Myoglobin stores O2 in muscles
D
None of the above
.
25.
Which hemoglobin chain replaces the beta chain in embryonic hemoglobulin?
A
Delta
.
B.Epsilon
C.Gamma
D
Alfa
.
26.
Hemoglobin has quaternary structure and is made up of
A
six polypeptide chains, two α-chains and four β-chains
.
B.two polypeptide chains, one α-chains and one β-chains
C.four polypeptide chains, two α-chains and two β-chains
D
five polypeptide chains, two α-chains and three β-chains
.
27.
When pO2 = Kd of myoglobin, the fractional saturation (YO2) is about
A
0.1
.
B.0.5
C.0.9
D
1.7
.
28.
Peptides in the fully extended chain conformation
A
have Y = F = 180°
.
B.do not occur in nature
C.also have a cis geometry in their peptide bonds
D
are equivalent to the (3-sheet structure
.
29.
The oxygen in hemoglobin and myoglobin is bound to
A
the iron atom in the heme group
.
B.the nitrogen atoms on the heme
C.histidine residues in the protein
D
lysine residues in the protein
.
30.
Which of the three subunits of the G proteins binds GDP and GTP?
A
Alpha
.
B.Beta
C.Gamma
D
Delta
.
31.
If the F and Y angles of each peptide unit in a protein are known, which of the following may also be
determined?
A
Complete secondary structure
.
B.Complete tertiary structure
C.Complete quaternary structure
D
Thermodynamic stability
.
32.
The different orders of protein structure are determined by all of the following bond types except
A
peptide bonds
.
B.phospho-diester bonds
C.disulfide bridges
D
hydrogen bonds
.
33.
The heme is held in place by a bond between
A
the Fe2+ and cysteine
.
B.the Fe3+ and histidine
C.the Fe3+ and cysteine
D
the Fe2+ and histidine
.
Hydrogen bonds in a-helices are
A
more numerous than Vander Waals interactions
.
B.not present at Phe residues
C.analogous to the steps in a spiral staircase
D
roughly parallel to the helix axis
.
2.
The peptide bond in proteins is
A
only found between proline residues
.
B.usually cis unless proline is the next amino acid
C.usually trans unless proline is the next amino acid
D
is planar because of steric hinderance
.
3.
The molecular formula for glycine is C2H5O2N. What would be the molecular formula for a linear oligomer
made by linking ten glycine molecules together by condensation synthesis?
A
C H O N
. 20 50 20 10
B.C20H32O11N10
C.C20H40O10N10
D
C H O N
. 20 68 29 10
4.
Which of the following is an example of tertiary structure in a protein?
A
A multimeric protein
.
B.An a-helix
C.A P-pleated sheet
D
A globular domain
.
5.
The peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with cyanogen bromide (CNBr) to produce:
A
Val-Lys + Glu-Met-Ser + Trp-Arg-Ala
.
B.Val-Lys-Glu-Met-Ser-Trp + Arg-Ala
C.Val-Lys-Glu-Met + Ser-Trp-Arg-Ala
D Val-Lys-Glu + Met-Ser-Trp-Arg-Ala
.
6.
In deoxy hemoglobin (Hb), the Fe (II) is coordinated to
A
four nitrogens of heme, the proximal His, and a water molecule
.
B.four nitrogens of heme and to a water molecule
C.two nitrogens of heme and to three His residues in Hb
D
two nitrogens of heme and to three water molecules
.
7.
In the β-pleated sheet
A
hydrogen bonds are formed between the peptide bonds
.
B.adjacent polypeptide chains can either be parallel or antiparallel
C.the polypeptide chain is fully extended
D
all of the above
.
8.
The Ramachandran Plot illustrates the fact that
A
the peptide bond is planar
.
B.the F & Y angles can assume any value in a peptide
C.the F & Y angles can assume only a single value in a protein
D
the F & Y angles can assume approximately three different values
.
9.
The resonance structures that can be drawn for the peptide bond indicate that the peptide bond
A
is stronger than an ordinary single bond
.
B.has partial double bond character
C.both (a) and (b)
D
is still not completely understood
.
10.
The major element of secondary structure in myoglobin and hemoglobin is
A
the P-strand
.
B.the a-helix
C.the reverse turn
D
All of these
.
11.
An oil drop with a polar coat is a metaphor referring to the three dimensional structure of
A
fibrous proteins
.
B.collagen
C.globular proteins
D
silk protein
.
Answer & Explanation
12.
What was the first protein whose complete tertiary structure was determined?
A
Lysozyme
.
B.Myoglobin
C.Pancreatic ribonuclease
D
Pancreatic DNase
.
13.
The peptide bond in proteins is
A
planar, but rotates to three preferred dihedral angles
.
B.nonpolar, but rotates to three preferred dihedral angles
C.nonpolar, and fixed in a trans conformation
D
planar, and usually found in a trans conformation
.
14.
In β-pleated sheet structures neighbouring
A
chains lie in a flat plane
.
B.neighboring residues are hydrogen bonded
C.neighboring chains are connected by a-helices
D
neighboring chains are hydrogen bonded
.
15.
The same peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala. was digested with chymotrypsin to produce
A
Val-Lys + Glu-Met-Ser + Trp-Arg-Ala.
.
B.Val-Lys-Glu-Met-Ser-Trp + Arg-Ala.
C.Val-Lys-Glu-Met-Ser + Trp-Arg-Ala.
D
Val-Lys-Glu-Met + Ser-Trp-Arg-Ala.
.
16.
Disulfide bonds most often stabilize the native structure of
A
extracellular proteins
.
B.dimeric proteins
C.hydrophobic proteins
D
intracellular proteins
.
Answer & Explanation
17.
Secondary structure in protein refers to
A
linear sequence of amino acids joined together by peptide bond
.
B.three dimensional arrangement of all amino acids in polypeptide chain
C.regular folding of regions of the polypeptide chain
D
protein made up of more than one polypeptide chain
.
18.
Heme is the binding pocket of myoglobin and hemoglobin and is composed of
A
negatively charged residues
.
B.polar residues
C.hydrophobic residues
D
positively charged residues
.
19.
What is the effect of a decrease in pH on hemoglobin oxygen affinity?
A
Decrease in oxygen affinity
.
B.Increase in oxygen affinity
C.No effect on oxygen affinity
D
Increase affinity in muscle cell otherwise decrease
.
Answer & Explanation
20.
What is the proportion of glycine residues in collagenous regions?
A
One-fourth
.
B.One-third
C.Half
D
One-tenth
.
21.
Which of the following statements is incorrect?
A
Protein G contains both a-helix and P-sheet
.
B.Protein G contains only a-helix
C.Fatty acid binding protein contains largely P-sheet
D
Hemoglobin contains four sub-units
.
22.
The oxygen binding curves of hemoglobin and myoglobin
A
allow maximum transfer of oxygen to the tissues
.
B.are a consequence of the quaternary structure of hemoglobin
C.both (a) and (b)
D
are identical
.
23.
The nature of peptide bond can be best explained as
A
partial double bond
.
B.truly double bond
C.Hydrogen bond
D
Van der waals force
.
24.
Which of the following statement is incorrect?
A
Hemoglobin and myoglobin are the two oxygen binding proteins
.
B.Hemoglobin transports O2 in the blood
C.Myoglobin stores O2 in muscles
D
None of the above
.
25.
Which hemoglobin chain replaces the beta chain in embryonic hemoglobulin?
A
Delta
.
B.Epsilon
C.Gamma
D
Alfa
.
26.
Hemoglobin has quaternary structure and is made up of
A
six polypeptide chains, two α-chains and four β-chains
.
B.two polypeptide chains, one α-chains and one β-chains
C.four polypeptide chains, two α-chains and two β-chains
D
five polypeptide chains, two α-chains and three β-chains
.
27.
When pO2 = Kd of myoglobin, the fractional saturation (YO2) is about
A
0.1
.
B.0.5
C.0.9
D
1.7
.
28.
Peptides in the fully extended chain conformation
A
have Y = F = 180°
.
B.do not occur in nature
C.also have a cis geometry in their peptide bonds
D
are equivalent to the (3-sheet structure
.
29.
The oxygen in hemoglobin and myoglobin is bound to
A
the iron atom in the heme group
.
B.the nitrogen atoms on the heme
C.histidine residues in the protein
D
lysine residues in the protein
.
30.
Which of the three subunits of the G proteins binds GDP and GTP?
A
Alpha
.
B.Beta
C.Gamma
D
Delta
.
31.
If the F and Y angles of each peptide unit in a protein are known, which of the following may also be
determined?
A
Complete secondary structure
.
B.Complete tertiary structure
C.Complete quaternary structure
D
Thermodynamic stability
.
32.
The different orders of protein structure are determined by all of the following bond types except
A
peptide bonds
.
B.phospho-diester bonds
C.disulfide bridges
D
hydrogen bonds
.
33.
The heme is held in place by a bond between
A
the Fe2+ and cysteine
.
B.the Fe3+ and histidine
C.the Fe3+ and cysteine
D
the Fe2+ and histidine
.
