Question 1

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 bonds 
A)  hydrogen bonds 
B)  disulfide bonds 
C)  Van der Waal bonds 
D)  ionic bonds

Question 2

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

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 3

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, Arg 
A)  His, Ser, Asp, Arg 
B)  Arg, His, Ser, Asp 
C)  His, Ser, Arg, Asp 
D)  Asp, Ser, His, Arg

Question 4

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 point 
A)  electric point 
B)  dipolar point 
C)  neutral point 
D)  isoelectric point

Question 5

What is the major organic product for the following reaction?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 6

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 F1F1F1S1F1F1F10-halo carboxylic acid with ammonia as the nucleophile. 
D)  Reaction of NH4Cl and NaCN with an aldehyde followed by an acidic work-up. 
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 F1F1F1S1F1F1F10-halo carboxylic acid with ammonia as the nucleophile. 
D)  Reaction of NH4Cl and NaCN with an aldehyde followed by an acidic work-up.

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 tetrapeptide 
A)  a protein 
B)  a polypeptide 
C)  a tripeptide 
D)  a tetrapeptide

Question 8

Which is the correct structure for the amino acid cysteine?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 9

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

Accepted Answer

A)  valine 
B)  serine 
C)  alanine 
D)  proline 
A)  valine 
B)  serine 
C)  alanine 
D)  proline

Question 10

What reagents would you use to convert acetaldehyde into alanine?

Accepted Answer

A)  NH3 
B)  HCN 
C)  NaCN, NH4Cl 
D)  NaNH2 
A)  NH3 
B)  HCN 
C)  NaCN, NH4Cl 
D)  NaNH2

Question 11

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

Accepted Answer

A)  diastereomers 
B)  meso 
C)  resolution 
D)  neutralization 
A)  diastereomers 
B)  meso 
C)  resolution 
D)  neutralization

Question 12

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)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 13

Which of the following compounds is not an amino acid?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 14

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. 
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.

Question 15

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. 
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.

Question 16

Which is the correct structure for serine?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 17

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

Accepted Answer

A)  cysteine 
B)  alanine 
C)  tyrosine 
D)  isoleucine 
A)  cysteine 
B)  alanine 
C)  tyrosine 
D)  isoleucine

Question 18

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

Accepted Answer

A)  alanine 
B)  valine 
C)  glycine 
D)  leucine 
A)  alanine 
B)  valine 
C)  glycine 
D)  leucine

Question 19

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

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 20

Which is the correct structure for the amino acid proline?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Exam 29: Amino Acids and Proteins

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

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

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).

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?

What is the major organic product for the following reaction?

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

What is formed by the combination of four amino acids?

Which is the correct structure for the amino acid cysteine?

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

What reagents would you use to convert acetaldehyde into alanine?

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

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

Which of the following compounds is not an amino acid?

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

Which of the following correctly describes the Merrifield synthesis?

Which is the correct structure for serine?

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

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

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

Which is the correct structure for the amino acid proline?

Structure and Bonding

Acids and Bases

Introduction to Organic Molecules and Functional Groups

Alkanes

Stereochemistry

Understanding Organic Reactions

Alkyl Halides and Nucleophilic Substitution

Alkyl Halides and Elimination Reactions

Alcohols, Ethers and Epoxides

Alkenes

Alkynes

Oxidation and Reduction

Mass Spectrometry and Infrared Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

Radical Reactions

Conjugation, Resonance, and Dienes

Benzene and Aromatic Compounds

Electrophilic Aromatic Substitution

Carboxylic Acids and the Acidity of the O-H Bond

Introduction to Carbonyl Chemistry; Organometallic Reagents; Oxidation and Reduction

Aldehydes and Ketones Nucleophilic Addition

Carboxylic Acids and Derivatives

Substitution Reactions of Carbonyl Compounds at the Alpha-Carbon

Carbonyl Condensation Reactions

Amines

Carbon-Carbon Bond Forming Reactions in Organic Synthesis

Pericyclic Reactions

Carbohydrates

Lipids

Synthetic Polymers

Filters

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).