Question 1

Which is the correct structure for serine?

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) B) and C)
F) A) and B)

Question 2

Reaction of a polypeptide, composed of 12 amino acids, with carboxypeptidase A releases Met (C-terminal amino acid) .The polypeptide undergoes partial hydrolysis to give 12 groups of peptides.Use the groups of overlapping amino acids to determine the proper sequence of this polypeptide.
Note: Since these lists of peptides are separated by commas, they are not necessarily in the proper sequence.
Ser, Lys, Trp-5. Met, Ala, Gly- 9. Lys, Ser Gly, 
His, Ala-6. Ser, Lys, Val -10. Glu, His, Val Glu, 
Val, Ser-7. Glu, His-11. Trp, Leu, Glu Leu, 
Glu, Ser-8. Leu, Lys, Trp-12. Ala, Met

Accepted Answer

A)  Met-Ala-Gly-His-Glu-Val-Ser-Lys-Trp-Leu-Glu-Ser
B)  Met-Ala-Gly-Glu-His-Ser-Val-Lys-Trp-Leu-Glu-Ser
C)  Ser-Glu-Leu-Trp-Lys-Ser-Val-Glu-His-Gly-Ala-Met
D)  Ser-Lys-Leu-Trp-Lys-Ser-Val-His-Glu-Gly-Ala-MetE) A) and D)
F) A) and C)

Question 3

Which one of the following naturally occurring amino acids does not have an S configuration?

Accepted Answer

A)  Cysteine
B)  Alanine
C)  Tyrosine
D)  IsoleucineE) B) and C)
F) A) and B)

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) None of the above
F) A) and C)

Question 5

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) A) and D)
F) A) and C) D

Question 6

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

Question 7

Why is the s-trans form of an amide bond more stable?

Accepted Answer

A)  There is no s-cis form in an amide bond.
B)  The oxygen is hydrogen-bonded with the nitrogen atom.
C)  The nitrogen is able to be sp2-hybridized.
D)  The more sterically bulky groups are farther apart.E) B) and D)
F) B) and C)

Question 8

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

Accepted Answer

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

Question 9

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

Accepted Answer

A)  Hemoglobin
B)  Keratins
C)  Collagens
D)  ElastinsE) A) and B)
F) All of the above

Question 10

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

Accepted Answer

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

Question 11

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) B) and C)
F) A) and D)

Question 12

What are the only non-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) B) and D)
F) C) and D) B

Question 13

Below is a proposed method for resolving a racemic mixture of (R) - and (S) -phenylalanine.Upon separation of the products, will this method produce (R) - or (S) -phenylalanine?

Accepted Answer

A)  (R) -Phenylalanine is produced since the acylase only hydrolyzes the amides of L-amino acids.
B)  (S) -Phenylalanine is produced since the acylase only hydrolyzes the amides of L-amino acids.
C)  (R) -Phenylalanine is produced since the acylase only hydrolyzes the amides of D-amino acids.
D)  (S) -Phenylalanine is produced since the acylase only hydrolyzes the amides of D-amino acids.E) A) and B)
F) None of the above

Question 14

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) B) and C)
F) A) and D)

Question 15

Which of the following amino acids is achiral?

Accepted Answer

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

Question 16

What is the major organic product for the following reaction?

Accepted Answer

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

Question 17

Which of the following correctly describes a protein?

Accepted Answer

A)  a dipeptide; two amino acids joined together by one amide bond
B)  a tripeptide; three amino acids joined together by two amide bonds
C)  a polymer of more than 40 amino acids joined together by amide bonds
D)  a polypeptide of any number of amino acids joined together by amide bondsE) B) and C)
F) A) and D)

Question 18

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

Question 19

What are the basic steps in the Merrifield peptide synthesis?

Accepted Answer

A)  Coupling and hydrolysis
B)  Hydrolysis and deprotection
C)  Deprotection and hydrogenation
D)  Coupling and deprotectionE) A) and B)
F) C) and D)

Question 20

Which of the following is the structure of the amino acid lysine?

Accepted Answer

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

Exam 29: Amino Acids and Proteins

Which is the correct structure for serine?

Correct Answer
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Correct Answer
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Which one of the following naturally occurring amino acids does not have an S configuration?

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

Correct Answer
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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) .

Correct Answer
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D

Which of the following correctly describes a peptide bond?

Correct Answer
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C

Why is the s-trans form of an amide bond more stable?

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

Correct Answer
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Which of the following is (are) globular protein(s) ?

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

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

Correct Answer
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What are the only non-covalent bonds that stabilize the tertiary structure of a peptide?

Correct Answer
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B

Below is a proposed method for resolving a racemic mixture of (R) - and (S) -phenylalanine.Upon separation of the products, will this method produce (R) - or (S) -phenylalanine?

Correct Answer
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Why can glycine not be resolved into two enantiomers?

Correct Answer
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Which of the following amino acids is achiral?

Correct Answer
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What is the major organic product for the following reaction?

Correct Answer
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Which of the following correctly describes a protein?

Correct Answer
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Which of the following correctly describes the Merrifield synthesis?

Correct Answer
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What are the basic steps in the Merrifield peptide synthesis?

Correct Answer
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Which of the following is the structure of the amino acid lysine?

Correct Answer
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Exam 29: Amino Acids and Proteins

Which is the correct structure for serine?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which one of the following naturally occurring amino acids does not have an S configuration?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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) .

Correct AnswerverifiedD

Which of the following correctly describes a peptide bond?

Correct AnswerverifiedC

Why is the s-trans form of an amide bond more stable?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedB

Below is a proposed method for resolving a racemic mixture of (R) - and (S) -phenylalanine.Upon separation of the products, will this method produce (R) - or (S) -phenylalanine?

Correct AnswerverifiedShow Answer

Why can glycine not be resolved into two enantiomers?

Correct AnswerverifiedShow Answer

Which of the following amino acids is achiral?

Correct AnswerverifiedShow Answer

What is the major organic product for the following reaction?

Correct AnswerverifiedShow Answer

Which of the following correctly describes a protein?

Correct AnswerverifiedShow Answer

Which of the following correctly describes the Merrifield synthesis?

Correct AnswerverifiedShow Answer

What are the basic steps in the Merrifield peptide synthesis?

Correct AnswerverifiedShow Answer

Which of the following is the structure of the amino acid lysine?

Correct AnswerverifiedShow Answer

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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) .

Correct Answer
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D

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C

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B

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