Question 1

What amino acid is at the C-terminus of the following peptide?

Accepted Answer

A)  Valine
B)  Serine
C)  Alanine
D)  ProlineE) B) and C)
F) A) and B)

Question 2

Which of the following is (are) fibrous protein(s) ?

Accepted Answer

A)  Keratins
B)  Hormones
C)  Enzymes
D)  AntibodiesE) A) and B)
F) B) and D)

Question 3

Which is the correct structure for the amino acid cysteine?

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) All of the above
F) B) and D)

Question 4

Which of the following is the major advantage of the Merrifield synthesis of peptides?

Accepted Answer

A)  It allows for the formation of absolutely no by-products.
B)  Impurities can be easily washed away.
C)  Excess reagent can be used.
D)  It prevents hydrogenation.E) A) and C)
F) B) and C)

Question 5

What is formed by the combination of four amino acids?

Accepted Answer

A)  A protein
B)  A polypeptide
C)  A tripeptide
D)  A tetrapeptideE) All of the above
F) A) and B)

Question 6

What is the product of the following reaction? (Assume workup to neutralize.)

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) B) and C)
F) A) and C)

Question 7

What are the only covalent bonds that stabilize the tertiary structure of a peptide?

Accepted Answer

A)  Hydrogen bonds
B)  Disulfide bonds
C)  Van der Waal bonds
D)  Ionic bondsE) All of the above
F) B) and C)

Question 8

What is (are) the missing reagent(s) in the reaction below? 3 B) HCN C) NaCN,NH4Cl D) NaNH2" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  NH3
B)  HCN
C)  NaCN,NH4Cl
D)  NaNH2E) A) and B)
F) All of the above

Question 9

What is the product of the following reaction? (Assume workup to neutralize.)

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) None of the above
F) A) and C)

Question 10

Give the order (1st to last) in which the following amino acids would be eluted with a buffer of pH = 4 from a column containing a cationic-exchange resin (Dowex 50) : Arg (pI = 10.8) ,Ser (pI = 5.7) ,Asp (pI = 2.8) and His (pI = 7.6) .

Accepted Answer

A)  His,Ser,Asp,Arg
B)  Arg,His,Ser,Asp
C)  His,Ser,Arg,Asp
D)  Asp,Ser,His,ArgE) B) and D)
F) B) and C)

Question 11

Which of the following correctly describes a peptide bond?

Accepted Answer

A)  a bond between sp3-hybridized atoms only
B)  a bond usually found in the s-cis conformation
C)  an amide bond
D)  the result of the formation of the carbonyl group of one amino acid with a R-group from the other amino acidE) A) and B)
F) A) and C)

Question 12

What is the configuration of naturally occurring amino acids?

Accepted Answer

A)  D
B)  S
C)  L
D)  RE) A) and B)
F) A) and C)

Question 13

Which of the following amino acids is achiral?

Accepted Answer

A)  Phenylalanine
B)  Glycine
C)  Valine
D)  AlanineE) B) and C)
F) A) and D)

Question 14

Which of the following is the correct structure for aspartic acid at pH = 1?

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) All of the above
F) A) and C)

Question 15

What is the product of the following reaction? (Assume workup to neutralize.)

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and B)
F) A) and C)

Question 16

What is the IUPAC or common name for the following compound?

Accepted Answer

A)  Cysteinylalanine
B)  Alanylcysteine
C)  Serinylalanine
D)  AlanylserineE) A) and D)
F) A) and C)

Question 17

Why can glycine not be resolved into two enantiomers?

Accepted Answer

A)  It has no stereogenic centers.
B)  It has no nitrogen atoms.
C)  It has no aromatic rings.
D)  It cannot be converted into a salt.E) All of the above
F) B) and C)

Question 18

Which of the following compounds is not an amino acid?

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) None of the above
F) C) and D)

Question 19

Which of the following correctly describes the tertiary structure of a peptide?

Accepted Answer

A)  the three-dimensional conformations of localized regions of a protein
B)  the particular sequence of amino acids that are joined together by peptide bonds
C)  the structure is defined by the b-pleated sheet form
D)  the three-dimensional shape adopted by the entire peptideE) B) and C)
F) All of the above

Question 20

Which of the following correctly describes the Merrifield synthesis?

Accepted Answer

A)  It uses a solid phase technique for the synthesis of peptides.
B)  It uses DCC (dicyclohexylcarbodiimide) to form the amide bond in a peptide synthesis.
C)  It uses BOC (tert-butoxycarbonyl) as a protecting group for peptide synthesis.
D)  It uses aqueous phase techniques for the synthesis of large polypeptides.E) A) and B)
F) None of the above

Exam 27: Amino Acids and Proteins

What amino acid is at the C-terminus of the following peptide?

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Which of the following is the major advantage of the Merrifield synthesis of peptides?

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Why can glycine not be resolved into two enantiomers?

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What are the only covalent bonds that stabilize the tertiary structure of a peptide?

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Which of the following correctly describes the tertiary structure of a peptide?

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What is formed by the combination of four amino acids?

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Which of the following compounds is not an amino acid?

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Which is the correct structure for the amino acid cysteine?

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What is the product of the following reaction? (Assume workup to neutralize.)

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What is the product of the following reaction? (Assume workup to neutralize.)

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What is the product of the following reaction? (Assume workup to neutralize.)

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Which of the following correctly describes the Merrifield synthesis?

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Which of the following is (are) fibrous protein(s) ?

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What is (are) the missing reagent(s) in the reaction below?

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What is the IUPAC or common name for the following compound?

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What is the configuration of naturally occurring amino acids?

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Give the order (1st to last) in which the following amino acids would be eluted with a buffer of pH = 4 from a column containing a cationic-exchange resin (Dowex 50) : Arg (pI = 10.8) ,Ser (pI = 5.7) ,Asp (pI = 2.8) and His (pI = 7.6) .

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Which of the following is the correct structure for aspartic acid at pH = 1?

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Which of the following amino acids is achiral?

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Which of the following correctly describes a peptide bond?

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Give the order (1^st to last) in which the following amino acids would be eluted with a buffer of pH = 4 from a column containing a cationic-exchange resin (Dowex 50) : Arg (pI = 10.8) ,Ser (pI = 5.7) ,Asp (pI = 2.8) and His (pI = 7.6) .

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