Question 1

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 2

What is the configuration of naturally occurring amino acids?

Accepted Answer

A) D 
B) S 
C) L 
D) R 
A) D 
B) S 
C) L 
D) R

Question 3

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 4

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

Question 5

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 6

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 7

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 8

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 9

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 peptide 
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 peptide

Question 10

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 11

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 12

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 13

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 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

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. 
A) They form amides. 
B) They form diastereomers. 
C) They form salts. 
D) They form meso compounds.

Exam 29: Amino Acids and Proteins

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

What is the configuration of naturally occurring amino acids?

Which of the following compounds is not an amino acid?

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

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

What is formed by the combination of four amino acids?

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

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

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

Which is the correct structure for the amino acid cysteine?

What reagents would you use to convert acetaldehyde into alanine?

What is the major organic product for the following reaction?

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?

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

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?

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 Related Compounds

Alkenes

Alkynes

Oxidation and Reduction

Mass Spectrometry and Infrared Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

Radical Reactions

Conjugation, Resonance, and Dienes

Benzene and Aromatic Compounds

Reactions of Aromatic Compounds

Carboxylic Acids and the Acidity of the O-H Bond

Introduction to Carbonyl Chemistry;

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

Synthetic Polymers

Lipids

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