Labster 4: SDS-PAGE

A researcher is working with a protein that contains four subunits of differing molecular weights. If the researcher performs SDS-PAGE, how many distinct bands should he see on the gel?

• One

• Two

• Three

• Four

In agarose gel, bands move to +ve changed electrode. However, in SDS-PAGE, bands move to -ve charged electrode.

• True

• False

Sodium Dodecyl Sulfate is a chemical that can reduce S=S bond

• True

• False

Which of the following is a primary factor that dictates how far a protein will migrate during SDS-PAGE?

• Size

• Degree of tertiary structure

• Number of subunits

• Degree of secondary structure

Which of the following is true about SDS-PAGE?

• It separates proteins by charge

• It is used to analyze DNA fragments

• The main ingredient in the gel is agarose

• It requires a protein-denaturing gel

• Staining with ethidium bromide allows visualization of results

A complex enzyme-S consists of two subunits of 10kD each, and two subunits of 20 kDa each. What is the size of band that will appear on SDS-PAGE (with Beta-mercaptoethanol treatment)?

• bands with 10kD and 20kD, respectively

• One band with 30 kDa

• bands with 20kD and 40kD, respectively

• One band with 60 kDa

After electrophoresis has completed, the band will appear after straining in Coomassie blue solution.

• True

• False

Coomassie blue has another name. It is?

• Smart Blue

• Superb Blue

• Cresyl blue

• Brilliant Blue

A heterodimer enzyme-X consists of a subunit of 20kD and a subunit of 35 kDa. What is the size of band that will appear on modified SDS-PAGE (without Beta-mercaptoethanol treatment)?

• two bands of 20kD and 35kD, respectively

• Three bands with 20kD, 35kD, and 55 kDa, respectively

• One band with 55 kDa

• Smear because separation will be poor

As opposed to electrophoresis with a more standard agar gel, what does polyacrylamide gel electrophoresis (PAGE) allow for when working with DNA?

• Running multiple lanes in one gel

• Resolution down to DNA strands with single base length differences

• Running multiple DNA strands in a single gel lane

• Staining the DNA for visualization