Question 1

Which amino acid has an indole ring in its side chain?

Accepted Answer

A)  tyrosine 
B)  tryptophan 
C)  isoleucine 
D)  asparagine 
E)  histidine 
A)  tyrosine 
B)  tryptophan 
C)  isoleucine 
D)  asparagine 
E)  histidine B

Question 2

The solid-phase method of peptide synthesis was devised by ________.

Accepted Answer

A)  Sanger 
B)  Merrifield 
C)  Edman 
D)  Strecker 
E)  Lister 
A)  Sanger 
B)  Merrifield 
C)  Edman 
D)  Strecker 
E)  Lister B

Question 3

Provide a reasonable synthesis of Gly-Val from the individual amino acids.

Accepted Answer

1) Glycine + benzyl chloroformate gives N-protected Z-Gly.
2) Z-Gly is activated with ethyl chloroformate.
3) Activated Z-Gly is treated with Val to form Z-Gly-Val.
4) Benzyloxycarbonyl protecting group is removed via catalytic hydrogenation to give Gly-Val.

Question 4

Which of the following reagents is used to protect the amino group of the N-terminal residue in solution-phase peptide synthesis?

Accepted Answer

A)  lithium diisopropyl amide 
B)  benzyl chloroformate 
C)  phenyl isothiocyanate 
D)  dicyclohexylcarbodiimide 
E)  trifluoroacetic acid 
A)  lithium diisopropyl amide 
B)  benzyl chloroformate 
C)  phenyl isothiocyanate 
D)  dicyclohexylcarbodiimide 
E)  trifluoroacetic acid

Question 5

Draw the Fischer projection of L-valine at a pH of 2.

Accepted Answer

The answer of Draw the Fischer projection of L-valine at...

Question 6

A protein bonded to a sugar residue would be classified as a ________.

Accepted Answer

A)  simple protein 
B)  glycoprotein 
C)  lipoprotein 
D)  metalloprotein 
E)  nucleoprotein 
A)  simple protein 
B)  glycoprotein 
C)  lipoprotein 
D)  metalloprotein 
E)  nucleoprotein

Question 7

Show where chymotrypsin would cleave the peptide shown below.

Accepted Answer

The answer of Show where chymotrypsin would cleave the peptide...

Question 8

The isoelectric point is important in ________.

Accepted Answer

A)  the enzymatic resolution of amino acids 
B)  electrophoresis 
C)  determination of the C-terminal amino acid 
D)  determination of the N-terminal amino acid 
E)  the ninhydrin test 
A)  the enzymatic resolution of amino acids 
B)  electrophoresis 
C)  determination of the C-terminal amino acid 
D)  determination of the N-terminal amino acid 
E)  the ninhydrin test

Question 9

Provide the structure of the predominant form of L-phenylalanine present in an aqueous solution at biological pH, pH = 7.4.

Accepted Answer

The answer of Provide the structure of the predominant form...

Question 10

When drawing a peptide, the N-terminus ________.

Accepted Answer

A)  is drawn on the right side 
B)  is drawn on the left side 
C)  is drawn as -NH2 
D)  B and C are both correct 
A)  is drawn on the right side 
B)  is drawn on the left side 
C)  is drawn as -NH2 
D)  B and C are both correct

Question 11

Provide the structure of the major organic product which results when L-phenylalanine is treated with a large excess of PhCH2OH and gaseous HCl.

Accepted Answer

Question 12

Which amino acid's side chain is positively charged at biological pH, pH = 7.4?

Accepted Answer

A)  arginine 
B)  tyrosine 
C)  aspartic acid 
D)  serine 
E)  glutamine 
A)  arginine 
B)  tyrosine 
C)  aspartic acid 
D)  serine 
E)  glutamine

Question 13

Which of the following structures is the neutral form of L-serine?

Accepted Answer

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

Question 14

Provide the structure of the predominant form of lysine present in an aqueous solution at biological pH, pH = 7.4.

Accepted Answer

The answer of Provide the structure of the predominant form...

Question 15

Even though we often write the structure of glycine as NH2CHCOOH, why does this not accurately represent the structure of the amino acid?

Accepted Answer

The acid/base properties of th

Question 16

Provide the structure of the predominant form of L-alanine present in an aqueous solution at pH 2.

Accepted Answer

The answer of Provide the structure of the predominant form...

Question 17

Provide the structure of the predominant form of L-valine present in an aqueous solution at biological pH, pH = 7.4.

Accepted Answer

The answer of Provide the structure of the predominant form...

Question 18

Provide a structure of the tripeptide YAP.

Accepted Answer

The answer of Provide a structure of the tripeptide YAP....

Question 19

Which of the following amino acids has its isoelectric point at the highest pH?

Accepted Answer

A)  glutamic acid 
B)  lysine 
C)  serine 
D)  histisdine 
E)  cysteine 
A)  glutamic acid 
B)  lysine 
C)  serine 
D)  histisdine 
E)  cysteine

Question 20

What is the name of the amino acid produced when propanoic acid is subjected to the following sequence of reagents:

Accepted Answer

A)  alanine 
B)  aspartic acid 
C)  glutamic acid 
D)  valine 
E)  asparagine 
A)  alanine 
B)  aspartic acid 
C)  glutamic acid 
D)  valine 
E)  asparagine

Exam 24: Amino Acids, Peptides, and Proteins

Which amino acid has an indole ring in its side chain?

The solid-phase method of peptide synthesis was devised by ________.

Provide a reasonable synthesis of Gly-Val from the individual amino acids.

Which of the following reagents is used to protect the amino group of the N-terminal residue in solution-phase peptide synthesis?

Draw the Fischer projection of L-valine at a pH of 2.

A protein bonded to a sugar residue would be classified as a ________.

Show where chymotrypsin would cleave the peptide shown below.

The isoelectric point is important in ________.

Provide the structure of the predominant form of L-phenylalanine present in an aqueous solution at biological pH, pH = 7.4.

When drawing a peptide, the N-terminus ________.

Provide the structure of the major organic product which results when L-phenylalanine is treated with a large excess of PhCH2OH and gaseous HCl.

Which amino acid's side chain is positively charged at biological pH, pH = 7.4?

Which of the following structures is the neutral form of L-serine?

Provide the structure of the predominant form of lysine present in an aqueous solution at biological pH, pH = 7.4.

Even though we often write the structure of glycine as NH2CHCOOH, why does this not accurately represent the structure of the amino acid?

Provide the structure of the predominant form of L-alanine present in an aqueous solution at pH 2.

Provide the structure of the predominant form of L-valine present in an aqueous solution at biological pH, pH = 7.4.

Provide a structure of the tripeptide YAP.

Which of the following amino acids has its isoelectric point at the highest pH?

What is the name of the amino acid produced when propanoic acid is subjected to the following sequence of reagents:

Structure and Bonding

Acids and Bases; Functional Groups

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides; Nucleophilic Substitution

Structure and Synthesis of Alkenes; Elimination

Reactions of Alkenes

Structure and Synthesis of Alcohols

Reactions of Alcohols

Infrared Spectroscopy and Mass Spectrometry

Nuclear Magnetic Resonance Spectroscopy

Ethers, Epoxides, and Thioethers

Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Aromatic Compounds

Reactions of Aromatic Compounds

Ketones and Aldehydes

Amines

Carboxylic Acids

Carboxylic Acid Derivatives

Condensations and Alpha Substitutions of Carboxyl Compounds

Carbohydrates and Nucleic Acids

Lipids

Synthetic Polymers

Filters

Provide the structure of the major organic product which results when L-phenylalanine is treated with a large excess of PhCH₂OH and gaseous HCl.

Even though we often write the structure of glycine as NH₂CHCOOH, why does this not accurately represent the structure of the amino acid?