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Structure and Properties of Peptides MCQ Questions & Answers

Structure and Properties of Peptides MCQs : This section focuses on the "Structure and Properties of Peptides". These Multiple Choice Questions (MCQs) should be practiced to improve the Structure and Properties of Peptides skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

When pO2 = Kd of myoglobin, the fractional saturation (YO2) is about

A. 0.1
B. 0.5
C. 0.9
D. 1.7

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Question 2

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

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Question 3

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

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Question 4

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

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Question 5

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

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Question 6

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

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Question 7

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. C20H50O20N10
B. C20H32O11N10
C. C20H40O10N10
D. C20H68O29N10

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Question 8

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

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Question 9

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

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Question 10

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

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Question 11

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

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Question 12

Which hemoglobin chain replaces the beta chain in embryonic hemoglobulin?

A. Delta
B. Epsilon
C. Gamma
D. Alfa

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Question 13

Which of the three subunits of the G proteins binds GDP and GTP?

A. Alpha
B. Beta
C. Gamma
D. Delta

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Question 14

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

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Question 15

What is the proportion of glycine residues in collagenous regions?

A. One-fourth
B. One-third
C. Half
D. One-tenth

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Question 16

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

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Question 17

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

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Question 18

Disulfide bonds most often stabilize the native structure of

A. extracellular proteins
B. dimeric proteins
C. hydrophobic proteins
D. intracellular proteins

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Question 19

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

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Question 20

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

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Question 21

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

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Question 22

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

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Question 23

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

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Question 24

What was the first protein whose complete tertiary structure was determined?

A. Lysozyme
B. Myoglobin
C. Pancreatic ribonuclease
D. Pancreatic DNase

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Question 25

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

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Question 26

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

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Question 27

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

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Question 28

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

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Question 29

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

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Question 30

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

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Question 31

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

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Question 32

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

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Question 33

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.

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