Question 1

A separation of a mixture of cations of different charge requires

Accepted Answer

A)  another cationic substance 
B)  an anionic substance 
C)  an electrically neutral, but highly polar, substance 
D)  an electrically neutral, nonpolar substance 
A)  another cationic substance 
B)  an anionic substance 
C)  an electrically neutral, but highly polar, substance 
D)  an electrically neutral, nonpolar substance

Question 2

The purity of an enzyme at various stages of purification is best measured by

Accepted Answer

A)  total protein. 
B)  total enzyme activity. 
C)  specific activity of the enzyme. 
D)  percent recovery of the protein. 
E)  percent recovery of the enzyme. 
A)  total protein. 
B)  total enzyme activity. 
C)  specific activity of the enzyme. 
D)  percent recovery of the protein. 
E)  percent recovery of the enzyme.

Question 3

The most efficient method for determining the sequence of a short peptide is:

Accepted Answer

A)  Edman degradation 
B)  Trypsin digestion 
C)  Chymotrypsin digestion 
D)  Cyanogen bromide digestion 
A)  Edman degradation 
B)  Trypsin digestion 
C)  Chymotrypsin digestion 
D)  Cyanogen bromide digestion

Question 4

Which separates on the basis of molecular weight?

Accepted Answer

A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange 
A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange

Question 5

Which would be best to separate a protein that binds strongly to its substrate?

Accepted Answer

A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange 
A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange

Question 6

Which would be best to separate proteins of similar size?

Accepted Answer

A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange 
A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange

Question 7

It is frequently possible to bypass the determination of the identity of the N-terminal amino acid of a protein because

Accepted Answer

A)  this information is already available from the amino acid analysis 
B)  the Edman method sequences the peptide from the N-terminal end 
C)  N-terminal amino acids are always chemically modified 
D)  this information is not needed 
A)  this information is already available from the amino acid analysis 
B)  the Edman method sequences the peptide from the N-terminal end 
C)  N-terminal amino acids are always chemically modified 
D)  this information is not needed

Question 8

Salting out with ammonium sulfate is based upon proteins interacting with other proteins via

Accepted Answer

A)  hydrogen bonds. 
B)  ionic bonds. 
C)  hydrophobic interactions. 
D)  disulfide bonds. 
A)  hydrogen bonds. 
B)  ionic bonds. 
C)  hydrophobic interactions. 
D)  disulfide bonds.

Question 9

Which substance would you expect to be eluted first from a molecular sieve column with a suitable degree of crosslinking?

Accepted Answer

A)  hemoglobin 
B)  myoglobin 
C)  2,3-bisphosphoglycerate 
D)  all would elute at the same rate 
A)  hemoglobin 
B)  myoglobin 
C)  2,3-bisphosphoglycerate 
D)  all would elute at the same rate

Question 10

Two dimensional separation methods

Accepted Answer

A)  lead to unreliable results 
B)  are not widely used because of their complexity 
C)  do not improve separation 
D)  consist of two separation methods applied in sequence 
A)  lead to unreliable results 
B)  are not widely used because of their complexity 
C)  do not improve separation 
D)  consist of two separation methods applied in sequence

Question 11

An amino acid analyzer is an instrument used to determine

Accepted Answer

A)  the sequence of amino acids in a polypeptide chain 
B)  the identity of N-terminal and C-terminal amino acids in a protein 
C)  the presence of modified amino acids in a protein 
D)  the identities and relative amounts of amino acids in a protein 
A)  the sequence of amino acids in a polypeptide chain 
B)  the identity of N-terminal and C-terminal amino acids in a protein 
C)  the presence of modified amino acids in a protein 
D)  the identities and relative amounts of amino acids in a protein

Question 12

Which of the following is not an example of column chromatography?

Accepted Answer

A)  ammonium sulfate fractionation 
B)  ion-exchange separation 
C)  HPLC 
D)  affinity separation 
A)  ammonium sulfate fractionation 
B)  ion-exchange separation 
C)  HPLC 
D)  affinity separation

Question 13

Which of the following treatments results in a polypeptide fragment with a homoserine lactone at the C-terminal end?

Accepted Answer

A)  trypsin 
B)  chymotrypsin 
C)  cyanogen bromide 
D)  Edman method 
A)  trypsin 
B)  chymotrypsin 
C)  cyanogen bromide 
D)  Edman method

Question 14

A chromatography technique where a solution of nonpolar compounds is put through a column that has a nonpolar liquid immobilized on an inert matrix is which type of chromatography?

Accepted Answer

A)  Gel filtration 
B)  Ion exchange 
C)  Affinity 
D)  HPLC 
E)  Reverse Phase HPLC 
A)  Gel filtration 
B)  Ion exchange 
C)  Affinity 
D)  HPLC 
E)  Reverse Phase HPLC

Question 15

Important steps in sequencing pure proteins include all of these except:

Accepted Answer

A)  Determining the amino acid composition 
B)  Determining the isoionic pH of the protein 
C)  Breaking the protein into smaller peptides 
D)  Determining the amino acids on the ends of the protein 
E)  Determining the amino acids on the ends of the smaller peptides 
A)  Determining the amino acid composition 
B)  Determining the isoionic pH of the protein 
C)  Breaking the protein into smaller peptides 
D)  Determining the amino acids on the ends of the protein 
E)  Determining the amino acids on the ends of the smaller peptides

Question 16

In chromatography the experimental setup always requires

Accepted Answer

A)  a stationary phase and a mobile phase 
B)  a spectrophotometric detecting device 
C)  a sample in which components differ in charge 
D)  a sample in which components differ in polarity 
A)  a stationary phase and a mobile phase 
B)  a spectrophotometric detecting device 
C)  a sample in which components differ in charge 
D)  a sample in which components differ in polarity

Question 17

If a protein with the sequence FEWPRQVDMARINE is treated with chymotrypsin,what will the products be?

Accepted Answer

A)  F EW PRQVMARINE 
B)  FE WPRQVD MARINE 
C)  FEWPR QVDMAR INE 
D)  FEWPRQVDM ARINE 
A)  F EW PRQVMARINE 
B)  FE WPRQVD MARINE 
C)  FEWPR QVDMAR INE 
D)  FEWPRQVDM ARINE

Question 18

Which of the following is not used in protein structure determination?

Accepted Answer

A)  digestion with proteolytic enzymes 
B)  the Edman method 
C)  treatment with cyanogen bromide 
D)  treatment with alkyl halides 
A)  digestion with proteolytic enzymes 
B)  the Edman method 
C)  treatment with cyanogen bromide 
D)  treatment with alkyl halides

Question 19

Which of the following happens as a protein is purified?

Accepted Answer

A)  the percent recovery and the fold purification both increase 
B)  the percent recovery and the fold purification both decrease 
C)  the percent recovery increases and the fold purification decreases 
D)  the percent recovery decreases and the fold purification increases 
A)  the percent recovery and the fold purification both increase 
B)  the percent recovery and the fold purification both decrease 
C)  the percent recovery increases and the fold purification decreases 
D)  the percent recovery decreases and the fold purification increases

Question 20

The isoelectric point is

Accepted Answer

A)  the pH at which a substance has no net charge 
B)  the pH at which a substance has a net positive charge 
C)  the pH at which a substance has a net negative charge 
D)  the pH at which a substance has no charge groups of any kind 
A)  the pH at which a substance has no net charge 
B)  the pH at which a substance has a net positive charge 
C)  the pH at which a substance has a net negative charge 
D)  the pH at which a substance has no charge groups of any kind

Exam 5: Protein Purification and Characterization Techniques

A separation of a mixture of cations of different charge requires

The purity of an enzyme at various stages of purification is best measured by

The most efficient method for determining the sequence of a short peptide is:

Which separates on the basis of molecular weight?

Which would be best to separate a protein that binds strongly to its substrate?

Which would be best to separate proteins of similar size?

It is frequently possible to bypass the determination of the identity of the N-terminal amino acid of a protein because

Salting out with ammonium sulfate is based upon proteins interacting with other proteins via

Which substance would you expect to be eluted first from a molecular sieve column with a suitable degree of crosslinking?

Two dimensional separation methods

An amino acid analyzer is an instrument used to determine

Which of the following is not an example of column chromatography?

Which of the following treatments results in a polypeptide fragment with a homoserine lactone at the C-terminal end?

A chromatography technique where a solution of nonpolar compounds is put through a column that has a nonpolar liquid immobilized on an inert matrix is which type of chromatography?

Important steps in sequencing pure proteins include all of these except:

In chromatography the experimental setup always requires

If a protein with the sequence FEWPRQVDMARINE is treated with chymotrypsin,what will the products be?

Which of the following is not used in protein structure determination?

Which of the following happens as a protein is purified?

The isoelectric point is

Biochemistry and the Organization of Cells

Water: The Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three-Dimensional Structure of Proteins

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: Biosynthesis of Rna

Protein Synthesis: Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

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