Last week in Sisters4Science at Reavis, we welcomed Ms. Joyce, and she taught us how to extract DNA from strawberries!
First, the Sisters shared with everyone what they already knew about DNA–Aaliyah remembered that it was in human cells, and Kemonte recognized DNA because it was used on the Jerry Springer Show to see if two people were related. Ms. Joyce and the Sisters agreed that DNA can be found in any living thing: humans, animals, plants, and even bacteria! Then we found out an easy way to see DNA (without a microscope).
Each of the girls took a strawberry in a ziploc bag and smashed it all up to break the cells. Then, we added “DNA extraction buffer” (soap, salt, and water) to the mashed strawberry. We poured our strawberry/buffer mixture through a coffee filter so that strawberry juice with DNA in it would drip down into a plastic cup, separate from proteins and cells and other strawberry bits. After a little bit, each Sister added the strawberry juice to a tube of alcohol, and when we swirled it around, we could see DNA in the tube! The Sisters observed that the DNA was whitish and gooey; Mahogany said it looked like saliva.
We closed the session by talking about contributions that women have made in DNA research: Rosalind Franklin was a scientist who was very important in discovering the structure of DNA, the double helix. Because the Sisters were able to take the small-scale model of strawberry DNA extraction and apply it to a larger concept or idea (like extracting DNA from human cells to test them and see if people are related), they earned the Discover Building Models badge. That’s the last badge; good job, Sisters!