2.  DNA is found in the cell of every living thing.  Proteins that help DNA maintain it’s form may obscure our ability to see the DNA so they must be removed.  Among eukaryotes, DNA is contained in the membrane wrapped nucleus.  The cell membrane is made of lipids with embedded proteins.

3. Gently chewing the inside of the mouth combined with a water mouth wash is used to dislodge epithelial cells lining the mouth Ample cell collection is critical for success.

4.  Which parts of the cell do you have to go through to remove the DNA?  Cell membrane  Cytoplasm  Nucleus  Proteins wrapped around the DNA

5.  Phospholipids are large molecules that won’t dissolve in water.  Hydrophilic head  Hydrophobic tail  Detergent (soap) is used to break open the cell and nuclear membranes, allowing the DNA to be released into the solution

6.  Recall that the DNA is tightly wrapped around histones.  DNA would be hard to see if the proteins were not removed.  Detergent also helps to separate DNA from proteins

7.  Add concentrated Salt solution  Na + ions of NaCI bind to the phosphate groups of DNA molecules, neutralizing the electric charge of the DNA molecules.  The addition of NaCI allows the DNA molecules to come together instead of repelling each other, thus making it easier for DNA to precipitate out of solution when alcohol is added. Na + O CH 2 O P O O O Base CH 2 O P O O O Base OH Sugar O

8.  DNA does not dissolve in alcohol.  The addition of cold alcohol makes the DNA clump together and precipitate out of solution. Precipitated DNA molecules appear as long pieces of fluffy, stringy, web-like strands. The larger, visible air bubbles “lift” the DNA out of solution, from the aqueous into the alcohol layer. (alcohol is less dense than water)

9. Using a disposable plastic transfer pipet, carefully transfer the fluffy DNA strands you extracted into the small glass vial. –Transfer as much of your DNA and as little alcohol as possible. –The vial should be filled no higher than 2 mm from the top of the neck of the vial.

10. Firmly push the trimmed plastic stopper cap into the neck of the vial to seal the glass vial. Apply a small drop of super glue to the inside of the silver cap. Slip the waxed cord through the silver cap.