Question 1

In the case of paper electrophoresis, a paper strip saturated with an aqueous buffer of predetermined pH serves as a bridge between the two _____.

Accepted Answer

The answer of In the case of paper electrophoresis, a...

Question 2

Which of the following dipeptides is L-Ser-L-Phe?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
A)  1 
B)  2 
C)  3 
D)  4

Question 3

In Phe-Ile-Ser-Asp-Gly-His-Gly-Tyr, the three-letter abbreviation for the C-terminal amino acid is ________.

Accepted Answer

The answer of In Phe-Ile-Ser-Asp-Gly-His-Gly-Tyr, the three-letter abbreviation for the...

Question 4

Consider the following form of phenylalanine.   This form would exist at a pH _______than the pI.

Accepted Answer

The answer of Consider the following form of phenylalanine. ...

Question 5

Identify the compound shown below. ​

Accepted Answer

A)  L-Thyroxine 
B)  L-Triiodothyronine 
C)  L-Omithine 
D)  L-Citrulline 
A)  L-Thyroxine 
B)  L-Triiodothyronine 
C)  L-Omithine 
D)  L-Citrulline

Question 6

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

Accepted Answer

A)  glutamine 
B)  glycine 
C)  glutamic acid 
D)  threonine 
A)  glutamine 
B)  glycine 
C)  glutamic acid 
D)  threonine

Question 7

A tetrapeptide contains the amino acids Phe, Ala, Gly, and Leu. Partial hydrolysis produces the dipeptides Phe-Ala, Ala-Gly, and Leu-Phe. The structure of the tetrapeptide is _________________________. Use the three-letter designations for the amino acids separated by dashes (-).

Accepted Answer

The answer of A tetrapeptide contains the amino acids Phe,...

Question 8

Which of the following reagents can be used to cleave a benzyloxycarbonyl protecting group from a peptide?

Accepted Answer

A)  H2/Pd 
B)  H2O 
C)  Na2CO3, H2O 
D)  LiAlH4 
A)  H2/Pd 
B)  H2O 
C)  Na2CO3, H2O 
D)  LiAlH4

Question 9

Hydrogen bonds, α-helices, and pleated sheets are properties of structure of proteins.

Accepted Answer

The answer of Hydrogen bonds, α-helices, and pleated sheets are...

Question 10

What are the products of the reaction of alanine and ninhydrin (shown below)?

Accepted Answer

The answer of What are the products of the reaction...

Question 11

Bradykinin is a nonapeptide, Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg. In addition to one mole of Arg, the following peptides are present after hydrolysis of bradykinin with chymotrypsin,
Arg-Pro-Pro-Gly-Phe-Ser and Pro-Phe

Accepted Answer

A) True 
 B)False

Question 12

For leucine the pI is the average of pKa1 and pKa2.

Accepted Answer

A) True 
 B)False

Question 13

Consider the following image.   This represents the quaternary structure of a protein.

Accepted Answer

A) True 
 B)False

Question 14

Identify the technique that has almost replaced the automated Edman degradation.

Accepted Answer

A)  Gas chromatography 
B)  Infrared spectroscopy 
C)  Mass spectroscopy 
D)  N-terminal Amino acid analysis 
A)  Gas chromatography 
B)  Infrared spectroscopy 
C)  Mass spectroscopy 
D)  N-terminal Amino acid analysis

Question 15

Ninhydrin is used to determine the N-terminal amino acid of a peptide.

Accepted Answer

A) True 
 B)False

Question 16

To what structural feature does the term "secondary 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 17

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 an octapeptide with a C-terminal valine.

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 18

Which of the following reagents can be used to cleave a benzyloxycarbonyl protecting group from a peptide?

Accepted Answer

A)  HBr, CH3CO2H 
B)  conc. NaOH 
C)  heat 
D)  NaCl, H2O 
A)  HBr, CH3CO2H 
B)  conc. NaOH 
C)  heat 
D)  NaCl, H2O

Question 19

What is the isoelectric point of serine (pKa of α-CO2H, 2.21; pKa of α-NH2, 9.15)?

Accepted Answer

A)  5.68 
B)  9.94 
C)  11.36 
D)  20.22 
A)  5.68 
B)  9.94 
C)  11.36 
D)  20.22

Question 20

Which of the following is not an endopeptidase?

Accepted Answer

A)  Trypsin 
B)  Chymotrypsin 
C)  Elastase 
D)  Carboxypeptidase A 
A)  Trypsin 
B)  Chymotrypsin 
C)  Elastase 
D)  Carboxypeptidase A

Exam 27: Amino Acids and Proteins

In the case of paper electrophoresis, a paper strip saturated with an aqueous buffer of predetermined pH serves as a bridge between the two _____.

Which of the following dipeptides is L-Ser-L-Phe?

In Phe-Ile-Ser-Asp-Gly-His-Gly-Tyr, the three-letter abbreviation for the C-terminal amino acid is ________.

Consider the following form of phenylalanine. This form would exist at a pH _______than the pI.

Identify the compound shown below. ​

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

A tetrapeptide contains the amino acids Phe, Ala, Gly, and Leu. Partial hydrolysis produces the dipeptides Phe-Ala, Ala-Gly, and Leu-Phe. The structure of the tetrapeptide is _________________________. Use the three-letter designations for the amino acids separated by dashes (-).

Which of the following reagents can be used to cleave a benzyloxycarbonyl protecting group from a peptide?

Hydrogen bonds, α-helices, and pleated sheets are properties of structure of proteins.

What are the products of the reaction of alanine and ninhydrin (shown below)?

Bradykinin is a nonapeptide, Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg. In addition to one mole of Arg, the following peptides are present after hydrolysis of bradykinin with chymotrypsin, Arg-Pro-Pro-Gly-Phe-Ser and Pro-Phe

For leucine the pI is the average of pKa1 and pKa2.

Consider the following image. This represents the quaternary structure of a protein.

Identify the technique that has almost replaced the automated Edman degradation.

Ninhydrin is used to determine the N-terminal amino acid of a peptide.

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

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 an octapeptide with a C-terminal valine.

Which of the following reagents can be used to cleave a benzyloxycarbonyl protecting group from a peptide?

What is the isoelectric point of serine (pKa of α-CO2H, 2.21; pKa of α-NH2, 9.15)?

Which of the following is not an endopeptidase?

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

Identify the compound shown below.

For leucine the pI is the average of pK_a1 and pK_a2.

What is the isoelectric point of serine (pK_a of α-CO₂H, 2.21; pK_a of α-NH₂, 9.15)?