QUESTIONS

1) Separation of proteins by gel electrophoresis is based on:
a) Relative size of proteins
b) Mobilities or migration rates in a charged electrical field
c) Charged species
d) Hydrophobicity of proteins

2) Which of the following statement about gel electrophoresis is FALSE?
a) Sodium dodecyl sulphate is added to the protein sample so as to give the proteins a net negative charge
b) Once the power supply is switched on, the proteins loaded into the wells of the polyacrylamide gel will migrate from cathode to anode
c) Samples are loaded into the stacking gel and separation of proteins only takes place in the resolving gel
d) Tracking dyes are often used to monitor migration of proteins

3) The percentage of acrylamide in the resolving gel is usually lower than the stacking gel so as to allow the proteins to migrate slower hence allowing better separation of the proteins
a) True
b) False

4) Molecular weight of an unknown protein maybe determined from gel electrophoresis by
a) Measuring the distance travelled from the well to the protein band
b) Measuring the Rf value and comparing to that of the molecular weight (MW) markers
c) Measuring the Rf value and obtaining the MW from the calibration plot of MW versus Rf values of standard markers
d) Measuring the Rf value and obtaining the MW from the calibration plot of In MW versus Rf values of standard markers

5) The non-denaturing gel electrophoresis may separate proteins based on its charge and size
a) True
b) False

6) Techniques that can be used to detect proteins separated by SDS-PAGE are as follows:
a) Radiolabelled proteins maybe pressed against a sheet of X-ray film
b) Coomassie blue-250
c) Silver staining
d) Heavy metal staining
e) All the above

7) In the preparation of polyacrylamide gel, the catalyst that is used to accelerate polymerization and cross linking of gel is
a) TEMED
b) APS (ammonium persulphate)
c) Acrylamide
d) Bisacrylamide
e) No answer

8) What are the application of SDS-PAGE gel electrophoresis
a) To get a DNA fingerprint for forensic analysis
b) To get a DNA fingerprint for paternity testing
c) To get a DNA fingerprint to understand the evolutionary relationships among organisms
d) To test for genes associated with a particular disease.
e) All the above


The answers: a, d, a, b, a, e, a, e