Question 1

What is the IUPAC or common name for the following compound?

Accepted Answer

A) Cysteinylalanine 
B) Alanylcysteine 
C) Serinylalanine 
D) Alanylserine 
A) Cysteinylalanine 
B) Alanylcysteine 
C) Serinylalanine 
D) Alanylserine

Question 2

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 3

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 4

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 5

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 6

Why can glycine not be resolved into two enantiomers?

Accepted Answer

A) It has no stereogenic centers. 
B) It has no nitrogen atoms. 
C) It has no aromatic rings. 
D) It cannot be converted into a salt. 
A) It has no stereogenic centers. 
B) It has no nitrogen atoms. 
C) It has no aromatic rings. 
D) It cannot be converted into a salt.

Question 7

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 8

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 9

Which of the following is the correct structure for aspartic acid at pH = 1?

Accepted Answer

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

Question 10

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 11

What is (are)the missing reagent(s)in the reaction below?

Accepted Answer

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

Question 12

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 13

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 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

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 16

Reaction of a polypeptide,composed of 12 amino acids,with carboxypeptidase A releases Met (C-terminal amino acid).The polypeptide undergoes partial hydrolysis to give 12 groups of peptides.Use the groups of overlapping amino acids to determine the proper sequence of this polypeptide.Note: Since these lists of peptides are separated by commas,they are not necessarily in the proper sequence. Ser,Lys,Trp-5.Met,Ala,Gly- 9.Lys,Ser
Gly,His,Ala-6.Ser,Lys,Val -10.Glu,His,Val
Glu,Val,Ser-7.Glu,His-11.Trp,Leu,Glu
Leu,Glu,Ser-8.Leu,Lys,Trp-12.Ala,Met

Accepted Answer

A) Met-Ala-Gly-His-Glu-Val-Ser-Lys-Trp-Leu-Glu-Ser 
B) Met-Ala-Gly-Glu-His-Ser-Val-Lys-Trp-Leu-Glu-Ser 
C) Ser-Glu-Leu-Trp-Lys-Ser-Val-Glu-His-Gly-Ala-Met 
D) Ser-Lys-Leu-Trp-Lys-Ser-Val-His-Glu-Gly-Ala-Met 
A) Met-Ala-Gly-His-Glu-Val-Ser-Lys-Trp-Leu-Glu-Ser 
B) Met-Ala-Gly-Glu-His-Ser-Val-Lys-Trp-Leu-Glu-Ser 
C) Ser-Glu-Leu-Trp-Lys-Ser-Val-Glu-His-Gly-Ala-Met 
D) Ser-Lys-Leu-Trp-Lys-Ser-Val-His-Glu-Gly-Ala-Met

Question 17

What are the only 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 18

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 19

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 20

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

Exam 27: Amino Acids and Proteins

What is the IUPAC or common name for the following compound?

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

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

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

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 can glycine not be resolved into two enantiomers?

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?

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

Which of the following is the correct structure for aspartic acid at pH = 1?

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

What is (are)the missing reagent(s)in the reaction below?

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 of the following correctly describes a protein?

Which is the correct structure for serine?

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

Which is the correct structure for the amino acid cysteine?

What are the basic steps in the Merrifield peptide synthesis?

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

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

Molecular Ion Peaks and Fragmentation Patterns

Analyzing Molecular Motion and Infrared Spectroscopy

Organic Spectroscopy Concepts

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