1. EXTRACTING HUMAN DNA

2. DNA DNA is the building block of life. DNA is the building block of life. It is present in every single cell. It is present in every single cell. It carry’s the code for every characteristic. It carry’s the code for every characteristic. It only consists of four molecules It only consists of four molecules Adenine Adenine Cytosine Cytosine Guanine Guanine Thymine Thymine

3. Equipment Needed Equipment Needed 1.5 litre of 0.9% salt solution (distilled water and table salt is ok) 1.5 litre of 0.9% salt solution (distilled water and table salt is ok) 1.5 litre of 25% detergent solution (distilled water and Surcare is ok) 1.5 litre of 25% detergent solution (distilled water and Surcare is ok) Ice-cold ethanol Ice-cold ethanol Plastic cups Plastic cups Boiling tubes Boiling tubes

4. Instructions 1.Chew the inside of your cheek for 1 minute. 2.Take a small mouthful of salt solution from your cup and swish it around for about a minute. 3.Spit the mouthwash into the plastic tube up to the 5ml level. 4.Add the detergent solution to the tube up to the 10ml level.

5. 5.Place cap on tube and gently invert for about a minute – do not shake. 6.Add ice-cold ethanol to the tube up to the 15ml level. 7.Allow to stand for 1 minute – if no strands of DNA are visible you may gently invert the tube again with the cap on. 8.Use a glass rod to remove the DNA, it can then be stored in ethanol in a small capsule or vial pendant.

6. The result you are looking for.. The ice cold ethanol causes the DNA to condense and so become visible.

7. What just happened… Cheek cells are removed from the mouth by the chewing and rinsing. Cheek cells are removed from the mouth by the chewing and rinsing. Cell membranes are dissolved by the detergent, releasing the DNA. Cell membranes are dissolved by the detergent, releasing the DNA. DNA will not dissolve in ethanol; instead it began to precipitate making it easy to see. DNA will not dissolve in ethanol; instead it began to precipitate making it easy to see.