Electrophoresis

Question 1

1. For proteins to migrate on a gel during electrophoresis, the isoelectric point must be exceeded. The
   isoelectric point of an amino acid or protein is defined
   as the:

a. ability of the amino acid or protein to carry both
positive and negative charges.
b. pH at which the amino acid or protein has a negative
charge.
c. pH at which a molecule has no net charge.
d. point on an electrophoretic gel at which that specific
protein migrates.

Answer 1

c. pH at which a molecule has no net charge.

Question 2

2. The term amphoteric means:

a. the pH at which a protein has no net charge.
b. that a protein will have a negative charge at a high pH.
c. that a protein has both positive and negative charges
because of its side chains.
d. the positive electrode.

Answer 2

c. that a protein has both positive and negative charges
because of its side chains

Question 3

3. Unequal migration of samples down the gel in an electrophoresis assay is an interference usually caused by:

a. dirty electrodes causing uneven application of the
electrical field.
b. dirty pipette tips or applicators.
c. too much sample being applied.
d. inappropriate binding of immunoglobulins to other
proteins in a sample

Answer 3

a. dirty electrodes causing uneven application of the
electrical field.

Question 4

4. In serum protein electrophoresis, the greater the charge
   of a molecule:

a. the slower it will migrate.
b. the faster it will migrate.
c. the less the migration rate will be affected.

Answer 4

b. the faster it will migrate.

Question 5

5. Serum protein electrophoresis is what kind of basic technique?

a. Immunoassay
b. Standardization
c. Qualitative technique
d. Separation

Answer 5

d. Separation

Question 6

6. Specimens with very low protein content sometimes
   require preconcentration before they are loaded onto an
   electrophoretic gel. An electrophoretic technique that
   does not require this concentration step is:

a. disc electrophoresis.
b. capillary electrophoresis.
c. zone electrophoresis.
d. two-dimensional gel electrophoresis

Answer 6

a. disc electrophoresis.

Question 7

7. What optical measuring technique allows for the scanning and quantification of electrophoretic fractions separated on a support medium?

a. Spectrophotometry
b. Chromatography
c. Densitometry
d. Nephelometry

Answer 7

c. Densitometry

Question 8

8. A Southern blot is used to detect fragments of:

a. RNA.
b. protein.
c. agarose.
d. DNA

Answer 8

d. DNA

Question 9

9. A 1% agarose gel is best suited for separating DNA fragments in which one of the following size ranges:

a. 500 bp (0.5 kbp) to 20 kbp
b. 50 to 100 kbp
c. 100 to 500 kbp
d. larger than 500 kbp

Answer 9

a. 500 bp (0.5 kbp) to 20 kbp

Question 10

10. The component of an electrophoresis system in which
    separation takes place is the:

a. stain.
b. support medium.
c. densitometer.
d. zone.

Answer 10

b. support medium.