Question

Electrophoresis Virtual Lab (11 Pts)

1. DNA will move toward which color electrode? What electrical charge does this pole have? What about the structure of DNA, specifically, is responsible for this behavior? (3)

3. What is the purpose of a DNA standard in your gel? (2)

5. Let’s analyze the following scenarios: A. gels were prepared and the DNA samples, along with a DNA standard were placed in the wells. After an hour running the gel, the samples seem to remain unmoved from their respective wells. What could have gone wrong? (1)

6. B. In a different run, you notice the colored running buffer moves up and out the top of the gel. Why might this have occurred? (1)

Answer 1

Ans 1. DNA will move towards red colour electrode, which is positively charged. The DNA is negatively charged due to its sugar-phosphate backbone.

Ans 3. the standard is used to check and identify the apporox size of DNA molecule running on the gel.

Ans 5. (A) the voltage of the gel running device is very low for running the gel or there must not be any DNA in the sample.  

Ans 6. (B) This is due to mistakenly place the electrode in opposite orientation while setting for the run. As DNA moves towards anode which is positively charged so it must be present or placed towards the top of the gel and cathode towards the bottom of the gel where anode is supposed to be present to make the correct the run of electrophoresis