CSI Strawberry DNA Experiment

Materials
Rubbing alcohol, measuring cups, salt, water, dish soap, bowl, test tube (glass), cheesecloth, funnel, 3 strawberries, ziplock bag, skewer.

 

Procedure
– Chill the rubbing alcohol in the freezer.
– Mix one half teaspoon of salt, 1/3 cup of water. and one tablespoon of dish soap liquid in a bowl. Set this mixture aside. This is your extraction liquid.
– Line the funnel with cheesecloth, so that it will drain into a test tube or glass. Not the glass with the extraction liquid.
– Remove the green stems from the strawberries.
– Put Strawberries into the ziplock bag and make sure all air is out of the bag. Then smash and squeeze the strawberries for 2 minutes.
– Now add 3 tablespoons of the extraction liquid you prepared to the strawberries in the bag.
– Now squeeze the strawberry mixture again for one more minute.
– Now pour the strawberry mixture from the bag into the funnel. Let it dip through the cheesecloth and into the glass or test tube.
– Measure 1/2 cup of rubbing alcohol.
– We use pipettes to slowly pour in the alcohol down the side into the strawberry liquid. You continue to do this until there is about 1 inch (2.54 cm) deep layer on top of the strawberry liquid. You might not need all of the rubbing alcohol.
– You should now see the strawberry DNA that will appear as a gooey clear/white stringy stuff.
– Now dip the skewer into the test tube and pull out some of the strawberry DNA.

 

Observation and results.
When we added the salt and dish soap mixture to the smashed strawberries, the dish soap help break open the strawberry cells, releasing the DNA into the solution, where as the salt help create different DNA strands that clump making it easier to see. The cold rubbing alcohol filtered the strawberry liquid and pulled out the DNA out of the liquid.

 

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