What are we made of? That’s a tricky question! Luckily, almost all living things have a built-in blueprint of all of their genetic information called DNA. With a little effort, we can extract strawberry DNA to take a closer look at this molecule!
What you need:
- 2 teaspoons of water
- ¼ teaspoon of dish soap
- ⅛ teaspoon of salt
- 1 cup of rubbing alcohol (chilled for 30 minutes)
- Plastic bag
- Paper towel
- Glass cup (able to see through)
- Rubber band
What you do:
First, place your strawberry in the plastic bag and seal it shut. Mash the strawberry until it’s all squished up!
Next, add the water, dish soap, and salt into the glass cup and stir. Pour this solution into the bag with the squished strawberry and continue to mash up the strawberry, combining it with the solution.
Then, cover the top of the glass with a paper towel and seal it in place with the rubber band. Gently, pour the strawberry mush out of the bag and on top of the paper towel on the cup. Let it sit for a few minutes to strain into the glass.
After a few minutes, remove the paper towel with the strawberry mush on it and throw it out. We want the strained out solution that dripped into the glass, as that’s where the strawberry DNA is!
Now, add the chilled rubbing alcohol into the cup with the strawberry solution. Observe to see if you can find any of the strawberry DNA floating around! It should look like white stringy bits in the glass. Pick it up and move it around with a toothpick.
Questions to consider:
- What is DNA?
- What does DNA tell us about living things?
- Could we extract the DNA out of other fruits?
Why it works:
DNA or deoxyribonucleic acid is the material containing genetic information found in (nearly) all living things.
When we mash up our strawberry and add the soap, we make it easier for the strawberry cells to release the DNA. The salt gives the strawberry DNA something to hold onto. By straining the mush, we are able to separate the DNA from the rest of the strawberry, and thus make it easier to see. The rubbing alcohol lets the DNA rise and move, making it even easier still to see.
This is possible with other fruits! Try using a kiwi or banana next!