electrophorisis lab questions

Focus Questions
1.  When you analyzed the results of your gel, did any of your experimental samples contain dyes that did
not match the four reference dyes? For example, did any of your samples produce:
a.  Dye bands that are a different size than any of the reference bands?
b.  Dyes that are a different color than any of the reference bands?
c.  More than one color band?
d.  Dyes that you observed moving in the “wrong” direction (toward the cathode)?
What might these dyes be?

yes. one sample contained orange skittle dye and it still contained the orange color when the lab was over. The orange dye was also bigger in width than the others at the end of the lab.


2.  Look at the structures of the dyes pictured here. Which of these dyes would migrate similarly to the dyes
you examined in this lab? Why?

Fast green FCF,  Citrus red 2, and Betanin would all have mostly the same affect as the dyes demonstraited in the lab because they contained similar dye colors and densities as the others.

3.  Many popular dry dog foods and dog treats have FD&C dyes among their ingredients. For example,
Beneful dry food contains Yellow 5, Red 40, Yellow 6, and Blue 2, and Snausages Breakfast Bites
contain Red 40 lake, Yellow 6 lake, and Yellow 5 lake. (Lake dyes are the insoluble forms of the FD&C
dyes.)
Why do dog food manufacturers put artificial food colors in dog food?

they put artificial color in dog food to give it a more appealing look and to gain the attention of the buyers. The dye doesn't change how the treats taste, or anything. The point of the colors is to make the food more appealing and appetizing.



5.  What two factors control the distance the colored dye solutions migrate?

the density and consentration of the dye are the main factors affecting how far the different colored dyes move in the gel. The conductivity of the dyes also has some factors involving how far the dyes move.

6.  What force helps move the dyes through the gel?

The amount of energy that flows through the gel between the conductivity points helps move the dyes through the gel. If the watts are turned up, then there will be more electricity flowing through the gel, and the colors will move away from the negative charge faster.

7.  What component of the electrophoresis system causes the molecules to separate by size? Explain

The molecules will separate by size due to the density of the dye in the molecule. The lighter and smaller molecules will move further along then the larger heavier ones. It is also easier for the lighter molecules to move away from the negative charge, then it is for the heavier larger ones to.


8.  Agarose electrophoresis is commonly used to separate molecules of DNA. Explain how you expect DNA
molecules with molecular weights of 600, 1000, 2000, and 5000 daltons to separate.

I would expect the DNA with the greater number of daltons to be separated into groups that also contain roughly the same number of daltons. The DNA samples that don't contain a large number of daltons would also be picked out and put together. The DNA is arranged by the number of daltons that the segments contain.