Question 1

What reagents would you use to convert acetaldehyde into alanine?

Accepted Answer

A)   NH3
B)   HCN
C)   NaCN, NH4Cl
D)   NaNH2E) C) and D)
F) B) and D)

Question 2

Which of the following is the correct structure for alanine at pH = 7?

Accepted Answer

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

Question 3

Which is the correct structure for the amino acid cysteine?

Accepted Answer

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

Question 4

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

Question 5

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

Accepted Answer

A)   valine
B)   serine
C)   alanine
D)   prolineE) B) and D)
F) C) and D)

Question 6

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 B)
F) B) and C)

Question 7

What is formed by the combination of four amino acids?

Accepted Answer

A)   a protein
B)   a polypeptide
C)   a tripeptide
D)   a tetrapeptideE) A) and B)
F) A) and D)

Question 8

Which is the correct structure for serine?

Accepted Answer

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

Question 9

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

Question 10

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

Accepted Answer

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

Question 11

Which of the following aldehydes would be a good starting material in the Strecker synthesis of phenylalanine?

Accepted Answer

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

Question 12

Which of the following compounds is not an amino acid?

Accepted Answer

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

Question 13

What is the separation of a racemic mixture into its component enantiomers called?

Accepted Answer

A)   diastereomers
B)   meso
C)   resolution
D)   neutralizationE) None of the above
F) A) and D)

Question 14

What is the name given to the pH at which the concentration of the zwitterionic form of an amino acid is at a maximum concentration?

Accepted Answer

A)   electric point
B)   dipolar point
C)   neutral point
D)   isoelectric pointE) A) and D)
F) B) and C)

Question 15

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 D)
F) A) and D)

Question 16

Amino acid synthesis is possible by all except one of the pathways listed. Which is not a synthetic pathway for amino acids?

Accepted Answer

A)   Amination of malonic ester followed by hydrolysis and decarboxylation.
B)   Nucleophilic addition of NH3 to an aldehyde followed by addition of cyanide to the imine, and, finally, hydrolysis.
C)   SN2 reaction using an -halo carboxylic acid with ammonia as the nucleophile.
D)   Reaction of NH4Cl and NaCN with an aldehyde followed by an acidic work-up.E) C) and D)
F) A) and D)

Question 17

Why do amide bonds exist as reasonably stable s-cis or s-trans isomers at room temperature?

Accepted Answer

A)   These amide bonds are not stable.
B)   There is partial double bond character between the carbonyl carbon and the nitrogen atom.
C)   The oxygen atom is hydrogen-bonded with the nitrogen atom.
D)   The side-chains can form hydrogen bonds.E) None of the above
F) B) and C)

Question 18

Which of the following amino acids does not have an L-isomer?

Accepted Answer

A)   alanine
B)   valine
C)   glycine
D)   leucineE) B) and C)
F) C) and D)

Question 19

What is the major organic product for the following reaction?

Accepted Answer

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

Question 20

Which is the correct structure for the amino acid proline?

Accepted Answer

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

Exam 29: Amino Acids and Proteins

What is the separation of a racemic mixture into its component enantiomers called?

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 AnswerverifiedShow Answer

Which of the following is the correct structure for alanine at pH = 7?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following aldehydes would be a good starting material in the Strecker synthesis of phenylalanine?

Correct AnswerverifiedShow Answer

Which is the correct structure for the amino acid cysteine?

Correct AnswerverifiedShow Answer

What reagents would you use to convert acetaldehyde into alanine?

Correct AnswerverifiedShow Answer

Which is the correct structure for the amino acid proline?

Correct AnswerverifiedShow Answer

Amino acid synthesis is possible by all except one of the pathways listed. Which is not a synthetic pathway for amino acids?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following correctly describes the Merrifield synthesis?

Correct AnswerverifiedShow Answer

What is the name given to the pH at which the concentration of the zwitterionic form of an amino acid is at a maximum concentration?

Correct AnswerverifiedShow Answer

Which is the correct structure for serine?

Correct AnswerverifiedShow Answer

What is the major organic product for the following reaction?

Correct AnswerverifiedShow Answer

Why do amide bonds exist as reasonably stable s-cis or s-trans isomers at room temperature?

Correct AnswerverifiedShow Answer

Which of the following compounds is not an amino acid?

Correct AnswerverifiedShow Answer

Which of the following amino acids does not have an L-isomer?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What is formed by the combination of four amino acids?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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) .

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