By The Thinkery
Have you ever seen a tiny seed turn into a fruit or vegetable over the course of a few months? Without DNA (deoxyribonucleic acid) none of this would be possible. DNA is contained in the cells of every living thing, and it’s the code that makes every living thing unique. This hands-on activity shows you how to isolate DNA from strawberries using common household objects.
- A resealable plastic bag
- A few fresh strawberries
- 1/2 cup water
- 1 tsp salt
- 2 tsp dish detergent
- 2 plastic cups
- Coffee filter
- 90 percent rubbing alcohol (chill in fridge beforehand for best results)
- Popsicle stick
What to do:
1. Remove the sepals (green leaves) from the strawberries.
2. Put the strawberries in a plastic bag and completely squish them using your fingers (be careful not to break the bag). This will release your strawberry DNA.
3. In a plastic cup, mix together the water, salt and dish detergent.
4. Add 2 tsp of the dish detergent mix into the bag with the strawberries, and gently continue mashing. This will help extract the DNA.
5. Put the coffee filter over the empty plastic cup and squeeze out the strawberry mash into the filter.
6. Once you have filtered the strawberry liquid, remove the filter, and slowly and gently pour the rubbing alcohol down the side into the cup. Lightly rock the cup back and forth, being careful not to splash.
7. Wait a minute or two. Can you see a separation of white mucus-like stuff collect at the top? That is the strawberry DNA! Try picking it out with your popsicle stick and examining it closer.
Try this activity with other fruit and vegetables. Which foods give you the most DNA?