Present your answers in complete sentences No need to rewrit

Present your answers in complete sentences. No need to rewrite the questions. Instead, to answer question 1, you can write, “In the virtual lab experiment, DNA microarrays were used to bla..bla…”.

Part I. Go through the electrophoresis virtual lab in the site below for answers to the questions:

http://learn.genetics.utah.edu/content/labs/gel/

1.Describe the main purpose of DNA electrophoresis.

2.What are the two main ingredients that are used to make a DNA gel?

3.Describe the composition and purpose of the buffer.

4.What is added to the DNA samples to help visualize them while loading into the gel wells?

5.During electrophoresis, what sign will you see in the buffer that will tell you that electric current is running?

6.What stain is used to see the DNA when the gel is exposed to UV light?

7.Describe the pattern of migration of DNA of different sizes.

8.There are 3 major DNA sizes in your sample. What are the sizes, in bases, of the three DNA fragments?

Solution

DNA Electrophoresis: It is a technique to separate DNA based on size of DNA molecule over the Agarose gel using electrical current. Agarose gel and buffer with appropriate pH The commonly used buffer for DNA electrophoresis is known as Tris acetate EDTA buffer (TAE), this is used to maintain the proper DNA integration at a specific pH. Gel loading dye The appearance of moving air bubbles in the gel indicate electric current is ongoing Ethidium bromide The small sized DNA will migrate out from the well first followed by larger size DNA molecules. The three major DNA sizes found are: 600bp, 3500bp, 1500bp