Extracting DNA from Strawberries – Food Science

Extract DNA from StrawberriesI originally published this post back in 2011, when I was teaching biology in a nearby town.  Since then, I left that school, went to teach in my hometown, and then promptly found myself unemployed.  Now, I am resuscitating my online presence and am thrilled that I can blend my 16 years of teaching science and cooking with kids into curriculum development.

Given the my experience teaching children to cook and eat healthy foods, it should come as no surprise that I liked to include food in my high school biology curriculum…

As we finished up a unit on cell division and DNA, my students were thrilled to find a large mug filled with strawberries on my desk this week on our lab day.  But they couldn’t get over the strange mixture of odors – the sweet fragrance of the berries combined with the vapors evaporating from our bottles of rubbing alcohol.  Like a fruit-doctor’s office!

The goal of our lab was to extract DNA from the berries, so they could see what it looks like with the naked eye.  It was simple to do, and can even be done at home with kids of any age.

Extract DNA with Everyday Ingredients and Tools

The best part of this lab was that we didn’t need any fancy-schmancy scientific equipment to complete the lab.  We only required a combination of ingredients and equipment that most households have handy.  (I know you probably don’t have a test tube – but I have a hunch that you have a shot glass!).

To set up the lab, we started by combining the mashed berries with a soap, salt and water mixture, which breaks down the phospholipid cell membranes.  Then we filtered the sludge through a double layer of cheesecloth.  One student suggested that we could have even used a coffee filter instead (which would have been a LOT cheaper).

After our filtrate was collected in a test tube, we added cold rubbing alcohol, which repelled the DNA molecules so they clumped together into a clear glob (somewhat similar to egg whites or mucus).

Then, we used a thin plastic loop to spool up the DNA and look at it.  If you were doing this lab at home, you could use a long wooden toothpick, BBQ skewer or chopstick.

If you would like to do this activity with your students or even your own children at home, you can find a full set of directions, along with printable laboratory sheets and analysis questions on my What’s Cooking with Kids Teachers Pay Teachers store.

Extract DNA from Strawberries

For other lesson plans that integrate cooking with other academic content, I have many lesson plans on my Teachers Pay Teachers page.  I also take requests – if you would like to integrate a cooking activity into your curriculum, let me know and I can design a lesson that includes relevant academic standards.  Thanks!

Love kitchen science? Here’s some more…
Ice Cream in a Bag
Cabbage Juice Chemistry

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4 Responses to Extracting DNA from Strawberries – Food Science

  1. very good idea!
    i like it and also try it,
    thanks for sharing to all..

  2. Pingback: Kitchen Science with Kids: Ice Cream in a BagWhat's Cooking With Kids

  3. Pingback: Cabbage Juice ChemistryWhat's Cooking With Kids

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