Question 1

Hydrophobic interaction chromatography can be used to separate proteins based on differences in

Accepted Answer

A) ionic charge. 
B) solubility. 
C) size. 
D) polarity. 
E) binding specificity. 
A) ionic charge. 
B) solubility. 
C) size. 
D) polarity. 
E) binding specificity.

Question 2

The salting in of proteins can be explained by:

Accepted Answer

A) salt counter-ions reducing electrostatic attractions between protein molecules. 
B) salt ions reducing the polarity of the solution. 
C) salt ions increasing the hydrophobic interactions. 
D) releasing hydrophobic proteins from nonpolar tissue environments. 
E) hydration of the salt ions reducing solubility of proteins. 
A) salt counter-ions reducing electrostatic attractions between protein molecules. 
B) salt ions reducing the polarity of the solution. 
C) salt ions increasing the hydrophobic interactions. 
D) releasing hydrophobic proteins from nonpolar tissue environments. 
E) hydration of the salt ions reducing solubility of proteins.

Question 3

A technique that can be used to separate proteins based primarily on the presence of non-polar residues on their surface is called

Accepted Answer

A) ion-exchange chromatography. 
B) gel filtration chromatography. 
C) affinity chromatography. 
D) gel electrophoresis. 
E) hydrophobic interaction chromatography. 
A) ion-exchange chromatography. 
B) gel filtration chromatography. 
C) affinity chromatography. 
D) gel electrophoresis. 
E) hydrophobic interaction chromatography.

Question 4

You are purifying a nuclease by affinity chromatography.To determine which fractions contain the protein of interest, you test samples of all fractions for their ability to break down DNA.This is an example of

Accepted Answer

A) a binding assay. 
B) a biological assay. 
C) an enzyme assay. 
D) an immunological assay. 
E) none of the above 
A) a binding assay. 
B) a biological assay. 
C) an enzyme assay. 
D) an immunological assay. 
E) none of the above

Question 5

Proteins are often constructed from multiple segments of 40-200 amino acid residues, commonly called

Accepted Answer

A) pseudogenes. 
B) hypervariable residues. 
C) protolytic fragments. 
D) domains. 
E) subunits. 
A) pseudogenes. 
B) hypervariable residues. 
C) protolytic fragments. 
D) domains. 
E) subunits.

Question 6

ELISA is an example of a(n):

Accepted Answer

A) enzyme assay. 
B) biological assay. 
C) binding assay. 
D) immunological assay. 
E) none of the above 
A) enzyme assay. 
B) biological assay. 
C) binding assay. 
D) immunological assay. 
E) none of the above

Question 7

We are able to purify proteins because they differ from each other in various physical or chemical properties.List 5 physicochemical properties of proteins that can be used as basis for their separation.Give a method of separation based on each of these properties (match the method with the property).

Accepted Answer

1.solubility - salting out; 2.ionic char

Question 8

A protein that has had few changes in its amino acid sequence over evolutionary history is labeled

Accepted Answer

A) a fibrinopeptide. 
B) evolutionarily conserved. 
C) random. 
D) a product of pseudogenes. 
E) phylogenetic. 
A) a fibrinopeptide. 
B) evolutionarily conserved. 
C) random. 
D) a product of pseudogenes. 
E) phylogenetic.

Question 9

Which of these reagents is commonly used to determine the number of polypeptides in a protein?

Accepted Answer

A) iodoacetate 
B) dansyl chloride 
C) 2-mercaptoethanol ($\beta$-M
E)  
D) cyanogen bromide 
E) DEAE 
A) iodoacetate 
B) dansyl chloride 
C) 2-mercaptoethanol ($\beta$-M
E)  
D) cyanogen bromide 
E) DEAE

Question 10

An enzyme-linked immunosorbent assay requires

Accepted Answer

A) a radioactive substrate. 
B) a radioactive standard for binding to the antibody. 
C) aromatic amino acids. 
D) an antibody that binds the protein of interest. 
E) a catalytic antibody. 
A) a radioactive substrate. 
B) a radioactive standard for binding to the antibody. 
C) aromatic amino acids. 
D) an antibody that binds the protein of interest. 
E) a catalytic antibody.

Question 11

What can be done to increase the rate at which a protein of interest moves down an ion-exchange chromatography column?

Accepted Answer

A) reduce the ion concentration in the eluant 
B) add a small amount of a non-ionic detergents to the eluant 
C) change the pH of the eluant 
D) add a protease inhibitor to the eluant 
E) reduce the temperature of the eluant 
A) reduce the ion concentration in the eluant 
B) add a small amount of a non-ionic detergents to the eluant 
C) change the pH of the eluant 
D) add a protease inhibitor to the eluant 
E) reduce the temperature of the eluant

Question 12

Matching
-In general, proteins are least soluble in water when the pH is close to the ______.

Accepted Answer

A) electrophoresis 
B) hydrophobic interaction 
C) enzyme-linked immunosorbent assay 
D) three-dimensional shape 
E) N-terminal amino acid
F)negative charge
G)nucleases
H)chromophore
I)foaming
J)high level expression
K)2-mercaptoethanol
L)positive charge
M)cation exchange
N)pI
O)chymotrypsin
P)C-terminal amino acid
Q)Sodium dodecyl sulfate 
A) electrophoresis 
B) hydrophobic interaction 
C) enzyme-linked immunosorbent assay 
D) three-dimensional shape 
E) N-terminal amino acid
F)negative charge
G)nucleases
H)chromophore
I)foaming
J)high level expression
K)2-mercaptoethanol
L)positive charge
M)cation exchange
N)pI
O)chymotrypsin
P)C-terminal amino acid
Q)Sodium dodecyl sulfate

Question 13

A radioimmunoassay requires

Accepted Answer

A) an enzyme-linked antibody. 
B) a coupled enzymatic reaction. 
C) a radiolabeled antibody. 
D) a catalytic antibody. 
E) a radiolabeled standard protein that is used to compete for binding to the antibody. 
A) an enzyme-linked antibody. 
B) a coupled enzymatic reaction. 
C) a radiolabeled antibody. 
D) a catalytic antibody. 
E) a radiolabeled standard protein that is used to compete for binding to the antibody.

Question 14

Matching
-If the cDNA for a protein has been cloned, it may be possible to obtain large quantities of the protein by _________________ in bacteria.

Accepted Answer

A) electrophoresis 
B) hydrophobic interaction 
C) enzyme-linked immunosorbent assay 
D) three-dimensional shape 
E) N-terminal amino acid
F)negative charge
G)nucleases
H)chromophore
I)foaming
J)high level expression
K)2-mercaptoethanol
L)positive charge
M)cation exchange
N)pI
O)chymotrypsin
P)C-terminal amino acid
Q)Sodium dodecyl sulfate 
A) electrophoresis 
B) hydrophobic interaction 
C) enzyme-linked immunosorbent assay 
D) three-dimensional shape 
E) N-terminal amino acid
F)negative charge
G)nucleases
H)chromophore
I)foaming
J)high level expression
K)2-mercaptoethanol
L)positive charge
M)cation exchange
N)pI
O)chymotrypsin
P)C-terminal amino acid
Q)Sodium dodecyl sulfate

Question 15

A technique that can be used to separate proteins based primarily on their pI is called

Accepted Answer

A) ion-exchange chromatography. 
B) gel filtration chromatography. 
C) affinity chromatography. 
D) isoelectric focusing. 
E) hydrophobic interaction chromatography. 
A) ion-exchange chromatography. 
B) gel filtration chromatography. 
C) affinity chromatography. 
D) isoelectric focusing. 
E) hydrophobic interaction chromatography.

Question 16

Matching
-Molecules that contain a(n)______ are capable of absorbing light.

Accepted Answer

A) electrophoresis 
B) hydrophobic interaction 
C) enzyme-linked immunosorbent assay 
D) three-dimensional shape 
E) N-terminal amino acid
F)negative charge
G)nucleases
H)chromophore
I)foaming
J)high level expression
K)2-mercaptoethanol
L)positive charge
M)cation exchange
N)pI
O)chymotrypsin
P)C-terminal amino acid
Q)Sodium dodecyl sulfate 
A) electrophoresis 
B) hydrophobic interaction 
C) enzyme-linked immunosorbent assay 
D) three-dimensional shape 
E) N-terminal amino acid
F)negative charge
G)nucleases
H)chromophore
I)foaming
J)high level expression
K)2-mercaptoethanol
L)positive charge
M)cation exchange
N)pI
O)chymotrypsin
P)C-terminal amino acid
Q)Sodium dodecyl sulfate

Question 17

A variety of chromatographic techniques are available for protein purification.
a.Explain briefly the principle of hydrophobic interaction chromatography.
b.Name three changes that can be made to the eluant that can be used to speed up elution of the protein of interest from a hydrophobic interaction chromatography column.

Accepted Answer

a.The column material is substituted wit

Question 18

Disulfide bonds can be cleaved using

Accepted Answer

A) iodoacetate. 
B) dansyl chloride. 
C) 2-mercaptoethanol ($\beta$-M
E) . 
D) trypsin. 
E) phenylisothiocyanate. 
A) iodoacetate. 
B) dansyl chloride. 
C) 2-mercaptoethanol ($\beta$-M
E) . 
D) trypsin. 
E) phenylisothiocyanate.

Question 19

Matching
-In ______ chromatography, a protein mixture must be applied to the column at a low pH so that the proteins will have a net positive charge and bind to the column.

Accepted Answer

A) electrophoresis 
B) hydrophobic interaction 
C) enzyme-linked immunosorbent assay 
D) three-dimensional shape 
E) N-terminal amino acid
F)negative charge
G)nucleases
H)chromophore
I)foaming
J)high level expression
K)2-mercaptoethanol
L)positive charge
M)cation exchange
N)pI
O)chymotrypsin
P)C-terminal amino acid
Q)Sodium dodecyl sulfate 
A) electrophoresis 
B) hydrophobic interaction 
C) enzyme-linked immunosorbent assay 
D) three-dimensional shape 
E) N-terminal amino acid
F)negative charge
G)nucleases
H)chromophore
I)foaming
J)high level expression
K)2-mercaptoethanol
L)positive charge
M)cation exchange
N)pI
O)chymotrypsin
P)C-terminal amino acid
Q)Sodium dodecyl sulfate

Question 20

You have purified the receptor for a hormone by affinity chromatography.During gel filtration chromatography under native conditions the receptor elutes between pyruvate decarboxylase (250 kDa)and glutamine synthetase (620 kDa).During SDS-PAGE, in the absence of reducing agents, the receptor migrates as a single band of approximately 230 kDa.When SDS-PAGE is carried out in the presence of 2-mercaptoethanol the receptor migrates as two bands of approximately 95 and 135 kDa.Explain this result.

Accepted Answer

The receptor is a heterotetramer compose

Exam 5: Proteins: Primary Structure

Hydrophobic interaction chromatography can be used to separate proteins based on differences in

The salting in of proteins can be explained by:

A technique that can be used to separate proteins based primarily on the presence of non-polar residues on their surface is called

You are purifying a nuclease by affinity chromatography.To determine which fractions contain the protein of interest, you test samples of all fractions for their ability to break down DNA.This is an example of

Proteins are often constructed from multiple segments of 40-200 amino acid residues, commonly called

ELISA is an example of a(n):

A protein that has had few changes in its amino acid sequence over evolutionary history is labeled

Which of these reagents is commonly used to determine the number of polypeptides in a protein?

An enzyme-linked immunosorbent assay requires

What can be done to increase the rate at which a protein of interest moves down an ion-exchange chromatography column?

Matching -In general, proteins are least soluble in water when the pH is close to the ______.

A radioimmunoassay requires

Matching -If the cDNA for a protein has been cloned, it may be possible to obtain large quantities of the protein by _________________ in bacteria.

A technique that can be used to separate proteins based primarily on their pI is called

Matching -Molecules that contain a(n)______ are capable of absorbing light.

Disulfide bonds can be cleaved using

Matching -In ______ chromatography, a protein mixture must be applied to the column at a low pH so that the proteins will have a net positive charge and bind to the column.

Introduction to the Chemistry of Life

Water

Nucleotides, Nucleic Acids, and Genetic Information

Amino Acids

Proteins: Three-Dimensional Structure

Protein Function Part I: Myoglobin and Hemoglobin

Carbohydrates

Lipids and Biological Membranes

Membrane Transport

Enzyme Catalysis

Enzyme Kinetics, Inhibition and Control

Biochemical Signaling

Introduction to Metabolism

Glycogen Metabolism and Gluconeogenesis

Glucose Catabolism

Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Mammalian Fuel Metabolism: Integration and Regulation

Nucleotide Metabolism

Nucleic Acid Structure

Dna Replication, Repair and Recombination

Transcription and Rna Processing

Translation

Regulation of Gene Expression

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