Question 1

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

Question 2

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

Question 3

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

Question 4

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

Question 5

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

Question 6

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

Question 7

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

Question 8

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

Question 9

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

Question 10

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

Question 11

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

Question 12

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

Question 13

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

Question 14

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

Question 15

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

Question 16

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.

Question 17

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

Question 18

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.

Question 19

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

Question 20

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

Exam 5: Protein Purification and Characterization Techniques

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Two dimensional separation methods

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

A separation of a mixture of cations of different charge requires

Correct AnswerverifiedShow Answer

Which separates on the basis of molecular weight?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which would be best to separate proteins of similar size?

Correct AnswerverifiedShow Answer

In chromatography the experimental setup always requires

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

An amino acid analyzer is an instrument used to determine

Correct AnswerverifiedShow Answer

Which of the following happens as a protein is purified?

Correct AnswerverifiedShow Answer

The isoelectric point is

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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