Question 1

Serum used as the sample for electrophoretic analysis in clinical laboratories contains many groups of macromolecules.Examples include amino acids, serum proteins, lipoproteins, glycoproteins, and others.Suppose an analyst is interested in performing serum protein electrophoresis.How does the analyst prevent other groups of macromolecules from interfering with the analysis of serum proteins?

Accepted Answer

A)  by selecting a medium that will only allow the electrophoretic migration of serum proteins
B)  by selecting an electrophoresis voltage that will only cause migration of serum proteins
C)  by selecting an electrophoresis time that will allow all other macromolecules to migrate completely off the medium and leave only serum proteins
D)  by selecting a stain that will only visualize the desired serum proteinsE) None of the above
F) A) and D)

Question 2

Which of the following proteins will show the greatest net negative charge in a pH 8.6 buffer?

Accepted Answer

A)  protein A with an isoelectric point of 7.5
B)  protein B with an isoelectric point of 8.0
C)  protein C with an isoelectric point of 8.6
D)  protein D with an isoelectric point of 9.6E) C) and D)
F) None of the above

Question 3

Which support medium is most used in immunoelectrophoresis?

Accepted Answer

A)  polyacrylamide gel
B)  agarose
C)  agar
D)  starch gelE) C) and D)
F) A) and B) B

Question 4

Considering serum protein electrophoresis using an agarose gel medium, the main purpose of the medium is:

Accepted Answer

A)  to allow electrophoretic migration of proteins to occur
B)  to provide a site to bind the protein to, once separation is complete
C)  to bind the stain for visualization of the separated proteins
D)  to prevent other macromolecules, such as lipids, from interfering with serum protein electrophoresisE) B) and C)
F) C) and D)

Question 5

Which of the following chemicals is used for fixation following serum protein electrophoresis?

Accepted Answer

A)  dilute acetic acid
B)  Ponceau S
C)  sodium dodecyl sulfate
D)  saturated sodium hydroxideE) None of the above
F) B) and C)

Question 6

The discontinuous solvent system used to enhance electrophoretic resolution in which movement comes to a stop because of a lack of net charge is:

Accepted Answer

A)  isotachophoresis
B)  disk electrophoresis
C)  isoelectric focusing
D)  gel electrophoresisE) B) and C)
F) All of the above

Question 7

The net charge of a macromolecule is determined by the total number of charged groups within the macromolecule.The charge associated with the zeta potential of a macromolecule in an electrophoretic environment compares in which of the following ways to the net charge on the macromolecule itself?

Accepted Answer

A)  The zeta potential is greater than the net charge.
B)  The zeta potential is less than the net charge.
C)  The zeta potential is equal to the net charge.
D)  The zeta potential has no relationship to the net charge.E) A) and B)
F) A) and C)

Question 8

In most types of electrophoresis, interactions between analyte and the support medium have been minimized.Which of the following types of electrophoresis considers analyte-medium interactions important?

Accepted Answer

A)  capillary electrophoresis
B)  micellar electrokinetic chromatography
C)  electroblotting
D)  electrochromatographyE) B) and C)
F) A) and C)

Question 9

Electro-osmosis is the migration of supporting medium counterions and solvent toward the appropriate electrode.This net flow of counterions and solvent is in the opposite direction to the migration of the macromolecules of interest.Which of the following statements best describes the effect of electro-osmosis?

Accepted Answer

A)  Electro-osmosis will only affect the final positions of the macromolecules but not their separation.
B)  Electro-osmosis will prevent macromolecule separation from occurring.
C)  Electro-osmosis is the mechanism by which electrophoretic separation of macromolecules occurs.
D)  Electro-osmosis only occurs in capillary electrophoresis and is the mechanism of separation in the relatively new technique.E) All of the above
F) A) and B)

Question 10

In routine clinical electrophoresis, the most common means used to provide quantitative information about the zones that have separated involves the use of:

Accepted Answer

A)  mass spectrometry
B)  densitometry
C)  laser-induced fluorescence
D)  electrochemical techniquesE) B) and C)
F) A) and D)

Question 11

Following electrophoresis, it was determined that the desired results were not obtained.All of the expected zones showed very slow migration.Which of the following would be a likely solution for this slow migration?

Accepted Answer

A)  change to a support medium with a smaller pore size
B)  decrease the voltage used for the analysis
C)  change the pH of the buffer to a value closer to the isoelectric point of the analytes
D)  decrease the ionic strength of the bufferE) All of the above
F) B) and C)

Question 12

It is known that pH influences the charge of an analyte and, if set appropriately, can enhance electrophoretic mobility.In an attempt to improve separation of serum proteins, the analyst set the pH of the buffer at an extremely basic level.Following electrophoresis, it was determined that the desired results were not achieved.Which of the following explains why the modification was not successful?

Accepted Answer

A)  At the very basic pH, the proteins may have been denatured.
B)  At the very basic pH, the proteins may have been dissociated.
C)  At the very basic pH, the fraction of current carried by buffer hydroxyl ions resulted in poorer separation.
D)  All of the above are possible explanations.E) A) and B)
F) A) and C)

Question 13

An increase in the ionic strength of the electrophoretic buffer while operating at constant current will cause the voltage to ________, the electrophoretic migration of macromolecules to ________, and the separation of macromolecules to _______.

Accepted Answer

A)  increase, increase, increase
B)  increase, increase, decrease
C)  decrease, decrease, increase
D)  decrease, decrease, decreaseE) B) and C)
F) B) and D)

Question 14

One advantage of capillary electrophoresis over other types of electrophoresis is the potential to separate uncharged analytes.The separation of uncharged analytes is made possible in this technique by:

Accepted Answer

A)  the very short migration distance, which allows diffused uncharged analytes to be isolated along with charged analytes
B)  the lack of electro-osmosis, allowing the migration of uncharged analytes
C)  the use of micelles
D)  the use of more powerful methods of detectionE) B) and D)
F) A) and B)

Question 15

Is the following statement true or false? Why?
"A thinner electrophoretic support is associated with a greater sensitivity."

Accepted Answer

A)  true because a thinner support will require less sample to produce a detectable spot
B)  true because a thinner support will allow more exposure to air
C)  false because a thinner support can hold less sample
D)  false because a thinner support can hold more solvent and effectively dilute the sampleE) A) and B)
F) None of the above

Question 16

Considering only the effect of time on electrophoretic separation, the separation of bands ________ with time, and diffusion of bands _______ with time.

Accepted Answer

A)  increases, increases
B)  increases, decreases
C)  decreases, increases
D)  decreases, decreasesE) B) and C)
F) All of the above

Question 17

What will be the effect on the final electrophoretic pattern when horizontal electrophoresis is used and the surface of the medium is open to air?

Accepted Answer

A)  All electrophoretic bands will remain on the side of the medium to which the sample was applied.
B)  All electrophoretic bands will appear on the opposite side of the medium to which the sample was applied.
C)  Convective flow will result in a distorted final electrophoretic pattern.
D)  The final electrophoretic pattern will be compressed.E) A) and D)
F) A) and C)

Question 18

An increase in which of the following would increase the movement of particles through a solution in electrophoresis?

Accepted Answer

A)  voltage applied to the electrophoretic system
B)  viscosity of the solvent
C)  size and symmetry of the particles
D)  all of the aboveE) B) and D)
F) A) and D) A

Question 19

If the ionic strength of the electrophoretic buffer is increased from 0.1 M to 1.0 M and the system is operated at the same fixed voltage when using each buffer concentration, which of the following describes the results that would likely be seen when using the 1.0 M buffer, as compared to the results seen with the 0.1 M buffer?

Accepted Answer

A)  Electrophoretic separation would be achieved in shorter time with the 1.0 M buffer, with greater resolution.
B)  The electrophoretic pattern would be distorted, and the macromolecules may be denatured when using the 1.0 M buffer.
C)  Electrophoretic separation would be achieved in shorter time with the 1.0 M buffer, with decreased resolution.
D)  The electrophoretic separation time would have to be increased 10-fold to account for the 10-fold increase in buffer concentration.E) B) and C)
F) C) and D)

Question 20

When considering the factors that influence the mobility of macromolecules, the relaxation effect would tend to ________ electrophoretic mobility, because there is a momentary ________.

Accepted Answer

A)  lower, formation of a double layer of charge about the macromolecule
B)  increase, neutralization of charge around the macromolecule
C)  lower, electrical field that acts in the opposite direction to the applied field
D)  increase, enhanced electrical field that acts in the same direction as the applied fieldE) B) and D)
F) B) and C) C

Exam 6: Electrophoresis

Correct Answer
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Which of the following proteins will show the greatest net negative charge in a pH 8.6 buffer?

Correct Answer
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Which support medium is most used in immunoelectrophoresis?

Correct Answer
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B

Considering serum protein electrophoresis using an agarose gel medium, the main purpose of the medium is:

Correct Answer
verified

Which of the following chemicals is used for fixation following serum protein electrophoresis?

Correct Answer
verified

The discontinuous solvent system used to enhance electrophoretic resolution in which movement comes to a stop because of a lack of net charge is:

Correct Answer
verified

The net charge of a macromolecule is determined by the total number of charged groups within the macromolecule.The charge associated with the zeta potential of a macromolecule in an electrophoretic environment compares in which of the following ways to the net charge on the macromolecule itself?

Correct Answer
verified

In most types of electrophoresis, interactions between analyte and the support medium have been minimized.Which of the following types of electrophoresis considers analyte-medium interactions important?

Correct Answer
verified

Correct Answer
verified

In routine clinical electrophoresis, the most common means used to provide quantitative information about the zones that have separated involves the use of:

Correct Answer
verified

Following electrophoresis, it was determined that the desired results were not obtained.All of the expected zones showed very slow migration.Which of the following would be a likely solution for this slow migration?

Correct Answer
verified

Correct Answer
verified

An increase in the ionic strength of the electrophoretic buffer while operating at constant current will cause the voltage to __, the electrophoretic migration of macromolecules to , and the separation of macromolecules to _.

Correct Answer
verified

One advantage of capillary electrophoresis over other types of electrophoresis is the potential to separate uncharged analytes.The separation of uncharged analytes is made possible in this technique by:

Correct Answer
verified

Is the following statement true or false? Why? "A thinner electrophoretic support is associated with a greater sensitivity."

Correct Answer
verified

Considering only the effect of time on electrophoretic separation, the separation of bands __ with time, and diffusion of bands _ with time.

Correct Answer
verified

What will be the effect on the final electrophoretic pattern when horizontal electrophoresis is used and the surface of the medium is open to air?

Correct Answer
verified

An increase in which of the following would increase the movement of particles through a solution in electrophoresis?

Correct Answer
verified
A

Correct Answer
verified

When considering the factors that influence the mobility of macromolecules, the relaxation effect would tend to electrophoretic mobility, because there is a momentary .

Correct Answer
verified
C

Exam 6: Electrophoresis

Correct AnswerverifiedShow Answer

Which of the following proteins will show the greatest net negative charge in a pH 8.6 buffer?

Correct AnswerverifiedShow Answer

Which support medium is most used in immunoelectrophoresis?

Correct AnswerverifiedB

Considering serum protein electrophoresis using an agarose gel medium, the main purpose of the medium is:

Correct AnswerverifiedShow Answer

Which of the following chemicals is used for fixation following serum protein electrophoresis?

Correct AnswerverifiedShow Answer

The discontinuous solvent system used to enhance electrophoretic resolution in which movement comes to a stop because of a lack of net charge is:

Correct AnswerverifiedShow Answer

The net charge of a macromolecule is determined by the total number of charged groups within the macromolecule.The charge associated with the zeta potential of a macromolecule in an electrophoretic environment compares in which of the following ways to the net charge on the macromolecule itself?

Correct AnswerverifiedShow Answer

In most types of electrophoresis, interactions between analyte and the support medium have been minimized.Which of the following types of electrophoresis considers analyte-medium interactions important?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

In routine clinical electrophoresis, the most common means used to provide quantitative information about the zones that have separated involves the use of:

Correct AnswerverifiedShow Answer

Following electrophoresis, it was determined that the desired results were not obtained.All of the expected zones showed very slow migration.Which of the following would be a likely solution for this slow migration?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

An increase in the ionic strength of the electrophoretic buffer while operating at constant current will cause the voltage to ________, the electrophoretic migration of macromolecules to ________, and the separation of macromolecules to _______.

Correct AnswerverifiedShow Answer

One advantage of capillary electrophoresis over other types of electrophoresis is the potential to separate uncharged analytes.The separation of uncharged analytes is made possible in this technique by:

Correct AnswerverifiedShow Answer

Is the following statement true or false? Why? "A thinner electrophoretic support is associated with a greater sensitivity."

Correct AnswerverifiedShow Answer

Considering only the effect of time on electrophoretic separation, the separation of bands ________ with time, and diffusion of bands _______ with time.

Correct AnswerverifiedShow Answer

What will be the effect on the final electrophoretic pattern when horizontal electrophoresis is used and the surface of the medium is open to air?

Correct AnswerverifiedShow Answer

An increase in which of the following would increase the movement of particles through a solution in electrophoresis?

Correct AnswerverifiedA

Correct AnswerverifiedShow Answer

When considering the factors that influence the mobility of macromolecules, the relaxation effect would tend to ________ electrophoretic mobility, because there is a momentary ________.

Correct AnswerverifiedC

Correct Answer
verified

Correct Answer
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Correct Answer
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B

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified

An increase in the ionic strength of the electrophoretic buffer while operating at constant current will cause the voltage to __, the electrophoretic migration of macromolecules to , and the separation of macromolecules to _.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Considering only the effect of time on electrophoretic separation, the separation of bands __ with time, and diffusion of bands _ with time.

Correct Answer
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Correct Answer
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Correct Answer
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A

Correct Answer
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When considering the factors that influence the mobility of macromolecules, the relaxation effect would tend to electrophoretic mobility, because there is a momentary .

Correct Answer
verified
C