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DNA Extraction Lab
Learn about the source of the DNA being used and the role of detergent in extracting DNA at this link:
http://learn.genetics.utah.edu/units/activities/wheatgerm/background.cfm

DNA Extraction
Items needed
1 scoop, glass stirring rod
1 10 ml graduated cylinder
Water and 10 to 20 grains of salt.
Dish washing liquid soap
90% Alcohol
Wheat Germ

Procedure:

Step 1: Fill your graduated cylinder up to the 2-ml mark with Wheat Germ. Add 10 to 20 grains of salt with your fingers.
Salt makes the solution similar to the salt content in cells.
Step 2: Fill your graduated cylinder with the Wheat Germ in it with water up to the 5-ml mark.

Step 3 : Place .5 ml (1 /2 ml) of soap into the wheat germ water mix. Three drops

Step 4: Gently, gently, and even more gently dip the rod in the soap, water and wheat germ to mix it. (The Soap will help break down the cellular walls and nuclear membranes of the wheat germ cells. This will free the DNA that is inside.)

Step 5: Fill your graduated cylinder up to and just past the 10 ml mark with Ethyl Alcohol.
DO NOT MIX IT.

Step 6: Watch the DNA begin to float in the alcohol.

Each each person write, (DNA Extraction Lab) on a half sheet of paper.
1. After step 6, what did you see in the alcohol and describe what it looked like?
2. What is another word or phrase for DNA?
3. What 4 nitrogenous bases are found in DNA?
4. What part of the cell did the DNA come from?
5. What usually keeps the DNA in its usual place in the cell?
6. What are cell membranes and nuclear membranes made of?
7. What does soap do to the stuff that membranes are made of?
8. Why do you think the soap helped to free the DNA?
9. DNA is less dense than water. Why does the DNA move up into the alcohol?
10. DNA has a positive charge and Salt has a negative charge. What is the purpose of the salt in this activity?