Question 1

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 A

Question 2

Which is the correct structure for the amino acid valine?

Accepted Answer

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

Question 3

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

Accepted Answer

A) Hemoglobin 
B) Keratins 
C) Collagens 
D) Elastins 
A) Hemoglobin 
B) Keratins 
C) Collagens 
D) Elastins A

Question 4

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 5

What is the product of the following reaction? (Assume workup to neutralize.)

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
A) I 
B) II 
C) III 
D) IV

Question 6

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

Question 7

What is the appropriate sequence of reaction conditions used to synthesize valine from acetamidomalonic ester?

Accepted Answer

A) (1)NaOH; (2)(CH3)2CHBr; (3)Cl2,H2O,heat 
B) (1)NaOCH2CH3; (2)(CH3)2CH2CHBr; (3)HCl,H2O,heat 
C) (1)NaOCH2CH3; (2)(CH3)2CHBr; (3)HCl,H2O,heat 
D) (1)NaOH; (2)CH3CH2CH2Br; (3)HCl,H2O,heat 
A) (1)NaOH; (2)(CH3)2CHBr; (3)Cl2,H2O,heat 
B) (1)NaOCH2CH3; (2)(CH3)2CH2CHBr; (3)HCl,H2O,heat 
C) (1)NaOCH2CH3; (2)(CH3)2CHBr; (3)HCl,H2O,heat 
D) (1)NaOH; (2)CH3CH2CH2Br; (3)HCl,H2O,heat

Question 8

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

Question 9

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 10

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 11

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 12

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 13

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 14

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 bonds 
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 bonds

Question 15

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. 
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.

Question 16

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.

Question 17

Below is a 2D chromatogram that shows the separation of five amino acids.In this technique,the amino acid mixture is first separated by chromatography using a polar solvent system.Then the plate is rotated 90°,and the amino acids are further separated by electrophoresis.Identify the spots obtained from a mixture of Trp,Glu,Lys,Ile and Thr.A table with isoelectric points is included to aid in solving this problem.   amino acid-pI value Trp-5.9
Glu-3.2
Lys-9.7
Ile-6.0
Thr-5.6

Accepted Answer

A) 1=Lys,2=Thr,3=Glu,4=Trp,5=Ile 
B) 1=Glu,2=Thr,3=Lys,4=Trp,5=Ile 
C) 1=Lys,2=Ile,3=Glu,4=Trp,5=Thr 
D) 1=Glu,2=Ile,3=Lys,4=Trp,5=Thr 
A) 1=Lys,2=Thr,3=Glu,4=Trp,5=Ile 
B) 1=Glu,2=Thr,3=Lys,4=Trp,5=Ile 
C) 1=Lys,2=Ile,3=Glu,4=Trp,5=Thr 
D) 1=Glu,2=Ile,3=Lys,4=Trp,5=Thr

Question 18

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 19

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

Accepted Answer

A) Valine 
B) Serine 
C) Alanine 
D) Proline 
A) Valine 
B) Serine 
C) Alanine 
D) Proline

Question 20

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

Exam 27: Amino Acids and Proteins

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

Which is the correct structure for the amino acid valine?

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

What reagents would you use to convert acetaldehyde into alanine?

What is the product of the following reaction? (Assume workup to neutralize.)

What are the basic steps in the Merrifield peptide synthesis?

What is the appropriate sequence of reaction conditions used to synthesize valine from acetamidomalonic ester?

Which is the correct structure for the amino acid proline?

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

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

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

Which is the correct structure for serine?

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

Which of the following correctly describes a protein?

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?

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?

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

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

What is the major organic product for the following reaction?

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 and Addition Reactions

Alkynes and Synthesis

Oxidation and Reduction

Radical Reactions

Conjugation,resonance,and Dienes

Benzene and Aromatic Compounds

Reactions of Aromatic Compounds

Introduction to Carbonyl Chemistry; Organometallic Reagents; Oxidation and Reduction

Aldehydes and Ketones - Nucleophilic Addition

Carboxylic Acids and the Acidity of the O-H Bond

Carboxylic Acids and Their Derivatives Nucleophilic Acyl Substitution

Substitution Reactions of Carbonyl Compounds at the a Carbon

Carbonyl Condensation Reactions

Amines

Carbon-Carbon Bond-Forming Reactions in Organic Synthesis

Pericyclic Reactions

Carbohydrates

Synthetic Polymers

Lipids

Spectroscopy A: Mass Spectrometry

Spectroscopy B: Infrared Spectroscopy

Spectroscopy C: Nuclear Magnetic Resonance Spectroscopy

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