Question 1

Which of the following tripeptides is not hydrolyzed by trypsin?

Accepted Answer

A)  Glu-Arg-Ser 
B)  Arg-Glu-Thr 
C)  Glu-Ser-Arg 
D)  Lys-Ser-Arg 
A)  Glu-Arg-Ser 
B)  Arg-Glu-Thr 
C)  Glu-Ser-Arg 
D)  Lys-Ser-Arg C

Question 2

Provide the major organic product of the following reaction that is used in the chemical synthesis of peptides.

Accepted Answer

The answer of Provide the major organic product of the...

Question 3

Which of the following amino acids contains two stereocenters?

Accepted Answer

A)  isoleucine 
B)  proline 
C)  phenylalanine 
D)  glutamine 
A)  isoleucine 
B)  proline 
C)  phenylalanine 
D)  glutamine A

Question 4

To what structural feature does the term "primary structure" refer?

Accepted Answer

A)  the sequence of amino acids in proteins 
B)  the overall folding pattern of proteins 
C)  the aggregation of polypeptides 
D)  the conformation of local regions of polypeptides 
A)  the sequence of amino acids in proteins 
B)  the overall folding pattern of proteins 
C)  the aggregation of polypeptides 
D)  the conformation of local regions of polypeptides

Question 5

The molecule shown below is an α-amino acid.

Accepted Answer

A) True 
 B)False

Question 6

MATCH a structure from the list below to each of the following terms. Place the letter of the structure in the blank to the left of the term which it describes.
-_____ is a carboxyl-protected amino acid.

Accepted Answer

A)   
B)   
C) Val−Phe−Leu−Met−Tyr−Pro−Gly−Trp−Cys−Glu 
D)   
E)  
F)Asp−Tyr−Ile−His−Pro−Phe−Arg−Val
G)BOC group
H) 
I) 
J) 
K) 
L)Val−Lys−Phe−Gly−Arg−Met−Arg−Phe
M)Z group 
A)   
B)   
C) Val−Phe−Leu−Met−Tyr−Pro−Gly−Trp−Cys−Glu 
D)   
E)  
F)Asp−Tyr−Ile−His−Pro−Phe−Arg−Val
G)BOC group
H) 
I) 
J) 
K) 
L)Val−Lys−Phe−Gly−Arg−Met−Arg−Phe
M)Z group

Question 7

Which of the following amino acids has an aromatic side chain?

Accepted Answer

A)  tyrosine 
B)  glutamine 
C)  aspargine 
D)  valine 
A)  tyrosine 
B)  glutamine 
C)  aspargine 
D)  valine

Question 8

How does phenyl isothiocyanate, Ph−N=C=S, react with a peptide in the Edman degradation?

Accepted Answer

A)  the sp carbon acts as an electrophile in a reaction with an amino group of the peptide 
B)  the sulfur acts as a nucleophile and adds to the carbon of the peptide bond 
C)  the nitrogen acts as a nucleophile and adds to the carbon of the peptide bond 
D)  the sp carbon acts as an electrophile in a reaction with a carboxylate of the peptide 
A)  the sp carbon acts as an electrophile in a reaction with an amino group of the peptide 
B)  the sulfur acts as a nucleophile and adds to the carbon of the peptide bond 
C)  the nitrogen acts as a nucleophile and adds to the carbon of the peptide bond 
D)  the sp carbon acts as an electrophile in a reaction with a carboxylate of the peptide

Question 9

Valylalanine and alanylvaline are constitutional isomers.

Accepted Answer

A) True 
 B)False

Question 10

Which of the following amino acids migrates to the negative electrode on paper electrophoresis at a pH of 7.0?

Accepted Answer

A)  lysine 
B)  aspartic acid 
C)  asparagine 
D)  glutamic acid 
A)  lysine 
B)  aspartic acid 
C)  asparagine 
D)  glutamic acid

Question 11

MATCH a structure from the list below to each of the following terms. Place the letter of the structure in the blank to the left of the term which it describes.
-_____ is the product of an Edman degradation.

Accepted Answer

A)   
B)   
C) Val−Phe−Leu−Met−Tyr−Pro−Gly−Trp−Cys−Glu 
D)   
E)  
F)Asp−Tyr−Ile−His−Pro−Phe−Arg−Val
G)BOC group
H) 
I) 
J) 
K) 
L)Val−Lys−Phe−Gly−Arg−Met−Arg−Phe
M)Z group 
A)   
B)   
C) Val−Phe−Leu−Met−Tyr−Pro−Gly−Trp−Cys−Glu 
D)   
E)  
F)Asp−Tyr−Ile−His−Pro−Phe−Arg−Val
G)BOC group
H) 
I) 
J) 
K) 
L)Val−Lys−Phe−Gly−Arg−Met−Arg−Phe
M)Z group

Question 12

The combination of the two sidechains of the given compounds leads to the formation of a special bond. Identify the type of bond formed. ​

Accepted Answer

A)  Disulfide bond 
B)  Disulfite bond 
C)  Hydrogen bond 
D)  Vibrational bond 
A)  Disulfide bond 
B)  Disulfite bond 
C)  Hydrogen bond 
D)  Vibrational bond

Question 13

Provide the structure of Ser-Ala.

Accepted Answer

The answer of Provide the structure of Ser-Ala....

Question 14

Which of the following amino acids has a non-polar side chain?

Accepted Answer

A)  histidine 
B)  arginine 
C)  glutamine 
D)  valine 
A)  histidine 
B)  arginine 
C)  glutamine 
D)  valine

Question 15

What is the isoelectric point of glutamic acid (pKa of α-CO2H, 2.10; pKa of β-CO2H, 4.07; pH of α-NH2, 9.47)?

Accepted Answer

A)  3.08 
B)  5.67 
C)  6.16 
D)  17.28 
A)  3.08 
B)  5.67 
C)  6.16 
D)  17.28

Question 16

Which of the following amino acids is a secondary amine?

Accepted Answer

A)  proline 
B)  glutamine 
C)  cysteine 
D)  aspargine 
A)  proline 
B)  glutamine 
C)  cysteine 
D)  aspargine

Question 17

Which of the bonds in the following structure is cleaved by cyanogen bromide?

Accepted Answer

A)  i 
B)  ii 
C)  iii 
D)  iv 
A)  i 
B)  ii 
C)  iii 
D)  iv

Question 18

Which of the following amino acids is not chiral?

Accepted Answer

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

Question 19

Structure _____ (shown below) will migrate toward the positive electrode in an electrophoresis experiment. $\begin{array}{ccc}
\mathrm{CH}_{3} \mathrm{CHCO}_{2}^{-} &\mathrm{CH}_{3} \mathrm{CHCO}_{2}^{-} &\mathrm{CH}_{3} \mathrm{CHCO}_{2} \mathrm{H}\|&|&|\{ }^{+} \mathrm{NH}_{3} & \mathrm{NH}_{2} &{ }^{+} \mathrm{NH}_{3}\I&II&III
\end{array}$

Accepted Answer

The answer of Structure _____ (shown below) will migrate toward...

Question 20

To what structural feature does the term "quaternary structure" refer?

Accepted Answer

A)  the sequence of amino acids in proteins 
B)  the overall folding pattern of proteins 
C)  the aggregation of polypeptides 
D)  the conformation of local regions of polypeptides 
A)  the sequence of amino acids in proteins 
B)  the overall folding pattern of proteins 
C)  the aggregation of polypeptides 
D)  the conformation of local regions of polypeptides

Exam 27: Amino Acids and Proteins

Which of the following tripeptides is not hydrolyzed by trypsin?

Provide the major organic product of the following reaction that is used in the chemical synthesis of peptides.

Which of the following amino acids contains two stereocenters?

To what structural feature does the term "primary structure" refer?

The molecule shown below is an α-amino acid.

MATCH a structure from the list below to each of the following terms. Place the letter of the structure in the blank to the left of the term which it describes. -_____ is a carboxyl-protected amino acid.

Which of the following amino acids has an aromatic side chain?

How does phenyl isothiocyanate, Ph−N=C=S, react with a peptide in the Edman degradation?

Valylalanine and alanylvaline are constitutional isomers.

Which of the following amino acids migrates to the negative electrode on paper electrophoresis at a pH of 7.0?

MATCH a structure from the list below to each of the following terms. Place the letter of the structure in the blank to the left of the term which it describes. -_____ is the product of an Edman degradation.

The combination of the two sidechains of the given compounds leads to the formation of a special bond. Identify the type of bond formed. ​

Provide the structure of Ser-Ala.

Which of the following amino acids has a non-polar side chain?

What is the isoelectric point of glutamic acid (pKa of α-CO2H, 2.10; pKa of β-CO2H, 4.07; pH of α-NH2, 9.47)?

Which of the following amino acids is a secondary amine?

Which of the bonds in the following structure is cleaved by cyanogen bromide?

Which of the following amino acids is not chiral?

Structure _____ (shown below) will migrate toward the positive electrode in an electrophoresis experiment. | | | I II III

To what structural feature does the term "quaternary structure" refer?

Covalent Bonding and Shapes of Molecules

Alkanes and Cycloalkanes

Stereoisomerism and Chirality

Acids and Bases

Alkenes: Bonding, Nomenclature, and Properties

Reactions of Alkenes

Alkynes

Haloalkanes, Halogenation, and Radical Reactions

Nucleophilic Substitution and Beta-Elimination

Alcohols

Ethers, Epoxides, and Sulfides

Infrared Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

Mass Spectrometry

An Introduction to Organometallic Compounds

Aldehydes and Ketones

Carboxylic Acids

Functional Derivatives of Carboxylic Acids

Enolate Anions and Enamines

Dienes, Conjugated Systems, and Pericyclic Reactions

Benzene and the Concept of Aromaticity

Reactions of Benzene and Its Derivatives

Amines

Catalytic Carbon-Carbon Bond Formation

Carbohydrates

Lipids

Nucleic Acids

Organic Polymer Chemistry

Filters

The combination of the two sidechains of the given compounds leads to the formation of a special bond. Identify the type of bond formed.

What is the isoelectric point of glutamic acid (pK_a of α-CO₂H, 2.10; pK_a of β-CO₂H, 4.07; pH of α-NH₂, 9.47)?