Safety Glasses Needed!
Strawberry DNA Extraction
Names:________________________________________
_______________________________________
Purpose: To extract DNA from a strawberry.
Materials:
1 zip-loc bag
1 coffee filter
1 rubber band
1 wooden craft stick
1 graduated cylinder
1 strawberry
10 ml DNA extraction buffer
15 ml ice-cold ethanol
Experimental Procedure:
1.
2.
3.
4.
5.
6.
7.
8.
READ ALL DIRECTIONS BEFORE BEGINNING!
Gather all materials except for the liquid components (ethanol and extraction buffer).
Place the strawberry in the freezer bag, take air out of bag and seal.
Mash up the strawberry for 2 minutes.
Add 10 ml of the extraction buffer to the bag. Remove air and seal.
Mash again for 1 minute. While 1 partner is mashing, the other must do step 7.
Drape the coffee filter over the opening of the cup. Secure it with the rubber band.
Pour the mashed strawberry mixture into the filter and let it drip into the bottom of the cup. This should take about
10 minutes.
While you wait for the solution to filter, complete the following questions:
1.
What is the purpose of mashing up the strawberry?
2.
What does the extraction buffer do? (Hint: extraction buffer contains soap. What does soap do when you wash your
hands?)
3.
What does the filter do?
Part II: Extracting the DNA
9.
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12.
One partner should pour 15 ml of ice-cold ethanol into the graduated cylinder.
Remove the coffee filter from the cup and discard in the trash.
Carefully pour alcohol into the strawberry extract.
Using the craft stick, carefully stir the solution.
Part III: Observations
13. Watch where the alcohol and the extract layers come in contact with each other. Keep the cup at eye level to see what
happens.
What do you see appearing? (Sketch what you see and make notes of any other observations.)
Notes:
Additional questions:
What happened when you added the alcohol to the filtrate?
What did the DNA look like?