Question 1

Which is the correct structure for the amino acid cysteine?

Accepted Answer

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

Question 2

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

Question 3

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

Accepted Answer

A)  Diastereomers
B)  Meso
C)  Resolution
D)  NeutralizationE) B) and D)
F) B) and C)

Question 4

What is the configuration of naturally occurring amino acids?

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

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

Question 7

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

Question 8

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) None of the above

Question 9

What is the major organic product for the following reaction?

Accepted Answer

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

Question 10

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

Accepted Answer

A)  Alanine
B)  Valine
C)  Glycine
D)  LeucineE) None of the above
F) C) and D)

Question 11

Why does the formation of salts of a racemic mixture of N-acetyl valine with a single enantiomer of a-methylbenzylamine enable the separation of the two enantiomers of N-acetyl valine?

Accepted Answer

A)  They form amides.
B)  They form diastereomers.
C)  They form salts.
D)  They form meso compounds.E) All of the above
F) A) and B)

Question 12

What reagents would you use to convert acetaldehyde into alanine?

Accepted Answer

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

Question 13

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) B) and D)

Question 14

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) C) and D)
F) All of the above

Question 15

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 a-halo carboxylic acid with ammonia as the nucleophile
D)  Reaction of NH4Cl and NaCN with an aldehyde followed by an acidic work-upE) A) and C)
F) B) and D)

Exam 29: Amino Acids and Proteins

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 Answer
verified

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

Correct Answer
verified

Why does the formation of salts of a racemic mixture of N-acetyl valine with a single enantiomer of a-methylbenzylamine enable the separation of the two enantiomers of N-acetyl valine?

Correct Answer
verified

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

Correct Answer
verified

What is formed by the combination of four amino acids?

Correct Answer
verified

What is the major organic product for the following reaction?

Correct Answer
verified

What reagents would you use to convert acetaldehyde into alanine?

Correct Answer
verified

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

Correct Answer
verified

Which is the correct structure for the amino acid cysteine?

Correct Answer
verified

What is the configuration of naturally occurring amino acids?

Correct Answer
verified

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

Correct Answer
verified

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

Correct Answer
verified

Which of the following compounds is not an amino acid?

Correct Answer
verified

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

Correct Answer
verified

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

Correct Answer
verified

Exam 29: Amino Acids and Proteins

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

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

Correct AnswerverifiedShow Answer

Why does the formation of salts of a racemic mixture of N-acetyl valine with a single enantiomer of a-methylbenzylamine enable the separation of the two enantiomers of N-acetyl valine?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What is formed by the combination of four amino acids?

Correct AnswerverifiedShow Answer

What is the major organic product for the following reaction?

Correct AnswerverifiedShow Answer

What reagents would you use to convert acetaldehyde into alanine?

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 is the configuration of naturally occurring amino acids?

Correct AnswerverifiedShow Answer

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

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

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

Correct Answer
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Correct Answer
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