Question 1

Proteins are synthesized in vivo by the translation of

Accepted Answer

A)  cDNA.
B)  tRNA.
C)  rRNA.
D)  exons.
E)  mRNA.F) All of the above
G) C) and D)

Question 2

Edman degradation can be used to

Accepted Answer

A)  identify the N-terminal amino acid of a polypeptide.
B)  identify the C-terminal amino acid of a polypeptide.
C)  separate the subunits of a multi-subunit protein.
D)  cleave a protein at specific sites.
E)  cleave disulfide bonds within a protein so that the individual polypeptides can be separated.F) B) and E)
G) C) and D)

Question 3

Matching

-One of the reasons the primary structure is important for a protein is that it determines the ______ the molecule adopts in aqueous solutions.

Accepted Answer

A)   electrophoresis
B)   hydrophobic interaction
C)   enzyme-linked immunosorbent assay
D)   three-dimensional shape
E)   N-terminal amino acidF)  negative chargeG)  nucleasesH)  chromophoreI)  foaming J)  high level expressionK)  2-mercaptoethanolL)  positive chargeM)  cation exchangeN)  pIO)  chymotrypsinP)  C-terminal amino acidQ)  Sodium dodecyl sulfateR) H) and Q)
S) G) and I)

Question 4

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...

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.F) A) and B)
G) B) and E)

Question 6

Matching

-To help prevent denaturation of proteins in solution,steps are taken to avoid _________ and adsorption to surfaces.

Accepted Answer

A)   electrophoresis
B)   hydrophobic interaction
C)   enzyme-linked immunosorbent assay
D)   three-dimensional shape
E)   N-terminal amino acidF)  negative chargeG)  nucleasesH)  chromophoreI)  foaming J)  high level expressionK)  2-mercaptoethanolL)  positive chargeM)  cation exchangeN)  pIO)  chymotrypsinP)  C-terminal amino acidQ)  Sodium dodecyl sulfateR) G) and N)
S) H) and L)

Question 7

Matching

-______ chromatography is a method of fractionating a protein mixture according to differences in polarity.

Accepted Answer

A)   electrophoresis
B)   hydrophobic interaction
C)   enzyme-linked immunosorbent assay
D)   three-dimensional shape
E)   N-terminal amino acidF)  negative chargeG)  nucleasesH)  chromophoreI)  foaming J)  high level expressionK)  2-mercaptoethanolL)  positive chargeM)  cation exchangeN)  pIO)  chymotrypsinP)  C-terminal amino acidQ)  Sodium dodecyl sulfateR) G) and L)
S) I) and M)

Question 8

Although a protein's primary sequence can be inferred from the nucleotide sequence,modifications such as ______ can be determined most easily by tandem mass spectrometry followed by protein database searching.

Accepted Answer

A)  phosphorylation
B)  disulfide crosslinks
C)  glycosylation
D)  acetylation
E)  all of the aboveF) A) and B)
G) A) and C)

Question 9

Enzymes that hydrolyze the internal peptide bonds (not the peptide bonds of the terminal amino acids) of a protein are classified as

Accepted Answer

A)  oxidoreductases.
B)  lyases.
C)  endopeptidases.
D)  nucleases.
E)  exopeptidases.F) B) and C)
G) D) and E)

Question 10

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 acidF)  negative chargeG)  nucleasesH)  chromophoreI)  foaming J)  high level expressionK)  2-mercaptoethanolL)  positive chargeM)  cation exchangeN)  pIO)  chymotrypsinP)  C-terminal amino acidQ)  Sodium dodecyl sulfateR) F) and Q)
S) A) and O)

Question 11

Which of the following amino acids would be first to elute at pH 8.0 from an anion-exchange column?

Accepted Answer

A)  lysine
B)  alanine
C)  glutamic acid
D)  asparagine
E)  glycineF) None of the above
G) A) and B)

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 acidF)  negative chargeG)  nucleasesH)  chromophoreI)  foaming J)  high level expressionK)  2-mercaptoethanolL)  positive chargeM)  cation exchangeN)  pIO)  chymotrypsinP)  C-terminal amino acidQ)  Sodium dodecyl sulfateR) F) and L)
S) B) and O)

Question 13

One technique commonly used in protein purification is chromatography.
a.Explain briefly the general principle of column chromatography
b.Name four types of chromatography and indicate for each of these types the basis for separation (match types of chromatography with the properties that form the basis for separation).

Accepted Answer

a.In chromatography there are two phases...

Question 14

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 aboveF) A) and B)
G) A) and C)

Question 15

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.F) A) and D)
G) B) and E)

Question 16

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.F) C) and E)
G) B) and E)

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

The positive charge on proteins in electrospray ionization mass spectrometry is the result of

Accepted Answer

A)  protons fired at the gas-phase protein molecules.
B)  protonated side chains of Asp and Glu residues.
C)  protonated side chains of Arg and Lys residues.
D)  a high pH.
E)  electrons fired at the gas-phase protein molecules.F) A) and B)
G) D) and E)

Question 19

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 charg...

Question 20

A fast and common method for determining the protein concentration in column effluent is

Accepted Answer

A)  tandem mass spectrometry.
B)  salting in with ammonium sulfate.
C)  drying a portion and weighing the solid.
D)  measuring light absorption at 280 nm.
E)  Edman degradation.F) D) and E)
G) B) and C)

Exam 5: Proteins: Primary Structure

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

Correct Answer
verified

Edman degradation can be used to

Correct Answer
verified

Correct Answer
verified
a.In chromatography there are two phases...
View Answer

Matching -To help prevent denaturation of proteins in solution,steps are taken to avoid _________ and adsorption to surfaces.

Correct Answer
verified

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

Correct Answer
verified

Which of the following amino acids would be first to elute at pH 8.0 from an anion-exchange column?

Correct Answer
verified

Matching -______ chromatography is a method of fractionating a protein mixture according to differences in polarity.

Correct Answer
verified

Proteins are synthesized in vivo by the translation of

Correct Answer
verified

The salting in of proteins can be explained by:

Correct Answer
verified

The positive charge on proteins in electrospray ionization mass spectrometry is the result of

Correct Answer
verified

Correct Answer
verified
a.The column material is substituted wit...
View Answer

Correct Answer
verified
The receptor is a heterotetramer compose...
View Answer

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

Correct Answer
verified

Matching -One of the reasons the primary structure is important for a protein is that it determines the ______ the molecule adopts in aqueous solutions.

Correct Answer
verified

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.

Correct Answer
verified

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

Correct Answer
verified

A fast and common method for determining the protein concentration in column effluent is

Correct Answer
verified

Enzymes that hydrolyze the internal peptide bonds (not the peptide bonds of the terminal amino acids) of a protein are classified as

Correct Answer
verified

Although a protein's primary sequence can be inferred from the nucleotide sequence,modifications such as ______ can be determined most easily by tandem mass spectrometry followed by protein database searching.

Correct Answer
verified

Correct Answer
verified
1.solubility - salting out;2.ionic charg...
View Answer

Exam 5: Proteins: Primary Structure

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

Correct AnswerverifiedShow Answer

Edman degradation can be used to

Correct AnswerverifiedShow Answer

Correct Answerverifieda.In chromatography there are two phases...View AnswerShow Answer

Matching -To help prevent denaturation of proteins in solution,steps are taken to avoid _________ and adsorption to surfaces.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following amino acids would be first to elute at pH 8.0 from an anion-exchange column?

Correct AnswerverifiedShow Answer

Matching -______ chromatography is a method of fractionating a protein mixture according to differences in polarity.

Correct AnswerverifiedShow Answer

Proteins are synthesized in vivo by the translation of

Correct AnswerverifiedShow Answer

The salting in of proteins can be explained by:

Correct AnswerverifiedShow Answer

The positive charge on proteins in electrospray ionization mass spectrometry is the result of

Correct AnswerverifiedShow Answer

Correct Answerverifieda.The column material is substituted wit...View AnswerShow Answer

Correct AnswerverifiedThe receptor is a heterotetramer compose...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

Matching -One of the reasons the primary structure is important for a protein is that it determines the ______ the molecule adopts in aqueous solutions.

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A fast and common method for determining the protein concentration in column effluent is

Correct AnswerverifiedShow Answer

Enzymes that hydrolyze the internal peptide bonds (not the peptide bonds of the terminal amino acids) of a protein are classified as

Correct AnswerverifiedShow Answer

Although a protein's primary sequence can be inferred from the nucleotide sequence,modifications such as ______ can be determined most easily by tandem mass spectrometry followed by protein database searching.

Correct AnswerverifiedShow Answer

Correct Answerverified1.solubility - salting out;2.ionic charg...View AnswerShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
a.In chromatography there are two phases...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
a.The column material is substituted wit...
View Answer

Correct Answer
verified
The receptor is a heterotetramer compose...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
1.solubility - salting out;2.ionic charg...
View Answer