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"Let us strive to make each moment beautiful."
Saint Francis DeSales
painting by Katie Bergenholtz

Science Investigations that all students should do Before High School #12: DNA Extraction

#12: DNA Extraction
Carefully pour only the liquid of the strawberries into a test tube. Try to avoid clumps of strawberries. I have my test tubes packed, so I used a clean spice jar.
Add 1/4 teaspoon of dish washing soap. Stir it up with a wooden skewer or just shake the tube around a little to mix together.
Very carefully add ice cold rubbing alcohol (from the refrigerator) to the test tube. You want the alcohol to remain on top of the strawberry juice.

Now just watch and see something amazing happen in just minutes.
We have DNA! The little white strands are what you are looking for.


The Science Behind It
In higher organisms like plants and animals, DNA is stored in a compartment called a nucleus where the long, string-like DNA is tightly coiled. To separate DNA from the organism that contains it, you have to break the cells apart (lysis), filter out the big pieces of cell parts and collect the remaining liquid, or supernatent, and add chemicals like salt and alcohol to separate (precipitate) the DNA from the rest of the supernatent.

4 comments:

  1. Wow! I didn't even think you could see DNA! Cool!

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  2. Oh, what fun! We have some strawberries in the fridge that are clearly begging for this experiment! Thanks for sharing, Phyllis.

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  3. Cool! It's easy enough for me and exciting enough for Jerry!

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  4. We totally failed trying with a kiwi or banana or whatever they suggest other than a strawberry...now I don't even remember. But, we had great fun building DNA models :)

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