Download Name: Avalon Draven Daily Date: 11-09

Name: Avalon Draven Daily
Date: 11-09-10
Period: 1st Period
DNA Extraction; Biotechniques Virtual Lab:
http://learn.genetics.utah.edu/content/labs/extraction/
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“DNA extractions are usually the first step in a longer lab process” ~ Slide 3 of 7
“...DNA needs to be first purified away from proteins and other cellular contaminants.” ~ Slide
3 of 7
Inside each nucleus (In cells) are two meters of DNA
Steps used to purify DNA from a cheek swab, according to the Virtual Lab:
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Collect cheek cells
Burst cells open to release DNA
Separate DNA from proteins and debris
Isolate concentrated DNA
Using a “Buccal Swab”, you drag it gently over your cheek to retrieve the cells onto the swab. Then,
you cut the swab into an eppendorf tube. Using a micropipettor, you add some lysis solution (lysis
originating from the greek word: to separate). Lysis contains two important ingredients: detergent, and
an enzyme called proteinase K. The detergent destroys the cell membrane and nucleus envelope,
causing the DNA to float out unharmed. So, closing the tube tightly, you place it in warm water. It
worked, but the DNA is still tightly wrapped around proteins called histones. However, the proteinase
in the lysis has a job; cutting that histones open and apart, away from the DNA. Taking the
micropipettor out of the warm water and opening it, take out the swab and add a touch of concentrated
salt solution to the tube. The salt causes the protein and other debris to clump together. Then, place the
tube in the centrifuge. Inside the centrifuge, it spins the tube at high speeds, so that the heavy chunks of
protein and debris sink to the bottom of the tub, while the DNA floats about. The chunks should appear
as a giant gray mass at the bottom. Using the micropipettor, suction out the liquid (full of DNA) and
place it into another, clear and clean eppendorf tube, leaving the gray mass of protein and debris
behind. Taking the micopipettor again, you place isopropyl alcohol. Shaking the tube around a few
times, you will witness the alcohol will cause the DNA to clump together into small groups. This is
done because DNA is not soluble (meaning it doesn't stay dissolved). Now, we will place the tube in
the centrifuge again, but don't freak out when you pull it out and all the DNA has floated to the bottom.
It was supposed to do that. Now, once you have pulled it out, use your micropipettor once more to
extract the liquid. You may now do whatever you would like with your DNA (us any fluid you choose
to re dissolve it, and remember, DNA is soluble, so it'll go back to shape).
Now, follow these instructions yourself:
http://learn.genetics.utah.edu/content/labs/extraction/howto/