DNA is the molecule that carries genetic information for all living organisms. It is a very small molecule that is packaged up very tightly in the nucleus of every cell. It is so small and so compact that it is impossible to see using a regular microscope. In this activity, you will learn how to expand DNA so that you can see it with your naked eye!!
Watch as Miss Kate demonstrates how to make the invisible visible.
- Dish Soap
- Strawberry (or banana or other soft fruit!)
- Ethanol (best if its cold!)
- Filter (cheesecloth, coffee filter, or paper towel)
- Plastic bag
- Measuring spoons
- To prepare your extraction buffer mix together 1/8 tsp salt, 3 Tbsp of water, and 1 Tsp of dish soap. Stir to combine.
- Place your piece of fruit into a ziplock bag, and carefully mash with you hands.
- Add 1 Tbsp of your extraction buffer to the bag and mash for 1 minute.
- Place your filter on top of a clean cup (you may want to secure it with a rubber band).
- Gently pour your strawberry/buffer mixture over the the filter and allow the juice to drip into the cup.
- After the juice has dripped into the cup, SLOWLY add a layer of ethanol on top by carefully spooning the cold ethanol down the side. Add enough ethanol so that you have a layer 1-2cm thick.
- Let sit for 2-3 minutes and then observe the DNA in the ethanol layer!
For more information on this topic, check out the following websites:
DNA from The Beginning: Learn everything you ever wanted to know about DNA!
“Fantastic DNA! extraction steps”: Watch the video to learn more about each step in the DNA extraction process.
“Physicists Confirm There’s a Second Layer of Information Hidden in Our DNA”: Learn about how the folding of DNA contributes to its function.
“DNA Structure and Replication: Crash Course Biology #10”: Watch the video to learn more about the structure of DNA!
“What is DNA and How Does It Work?”: Watch the video to learn how DNA acts as a blue print for living things.
Classroom Teachers! Download the student worksheet and instructor guide to complete activity with your students.