Strawberry DNA Experiment Steve Spangler Science
In this lab, you extract and isolate DNA from strawberries using simple, household ingredients.
Strawberry DNA Experiment from Steve Spangler Science
You’ve probably learned about or heard about DNA, but have you ever seen it with your own eyes? In our cool Strawberry DNA Experiment, you’ll be able to extract, isolate and observe the DNA of a strawberry in a matter of minutes! Sound impossible? It’s not! Thanks to special characteristics of strawberries, observing its DNA is very possible — and super easy! You don’t have to be a geneticist and you don’t need an electron microscope. It’s easy, fun and all you need are a few household materials that you likely have on hand.
Food Science Experiments for Kids
All living things have DNA, which is short for deoxyribonucleic acid (say that three times!). DNA is the blueprint for everything that occurs inside an organism’s cells; each cell has a copy of the same set of instructions, which is called a “genome.” DNA tells an organism how to function and how to develop. Strawberry DNA is special: it has more DNA than any other fruit. In addition to this increased quantity, it also has a whopping eight copies of each DNA chromosome!
Extraction of DNA Made Easy
In this lab, you will extract and isolate DNA from strawberries using simple, household ingredients. The easy-to-follow instructions below will guide you in this hands-on experiment, which will teach children about food science. Create your very own strawberry DNA extraction lab and discuss what you’ve learned. This strawberry DNA experiment is a great way to talk about how DNA works, its functions and its importance in the makeup of each and every living organism. Looking for more great at-home experiments? Don’t miss our huge library of online experiments. We also have all-in-one science kits and at-home experiments that will inspire and get your kids or students excited about STEM subjects!
- Isopropyl alcohol (5 mL)
- Dish soap (10 mL)
- Salt (1/4 tsp)
- Zipper-lock bag
- Water (90 mL)
- Measuring cups and spoons
- Small glass container
- Pipette (optional)
Put a bottle of isopropyl alcohol in a freezer. We’ll come back to it later. Measure 6T (90 ml) of water into a small glass container.
Add 2 tsp (10 ml) dish soap to the water.
Stir in a ¼-tsp salt and mix until the salt dissolves. This is the extraction mixture.
Place one strawberry into a plastic zipper-lock bag.
Pour the extraction mixture into the bag with the strawberry.
Remove as much air from the bag as possible and seal it closed.
Use your hands and fingers to mash, smash, and moosh the strawberry inside of the bag. You don’t want any large pieces remaining.
Pour the resulting strawberry pulp and extraction mixture through a strainer and into a medium glass bowl or similar container.
Use a spoon to press the mashed bits of strawberry against the strainer forcing even more of the mixture into the container. From the container it’s in now, pour the extraction mixture into a smaller glass container that holds ¼- to ½-cup (50-100 ml) of fluid. This will help to isolate the DNA on the surface of the mixture.
Add 1 tsp (5 ml) of the chilled isopropyl alcohol to the solution and hold the mixture at eye level. You’re looking for a separation of material that shows up as a white layer on top. That’s the DNA of the strawberry!
Use the tweezers to gently remove the DNA from the solution and lay it on a dish to examine.
How Does It Work
Whoa! The long thick fibers you pull out of the extraction mixture are real strands of strawberry DNA. As you may know, DNA is present in every cell of all plants and animals and determines all genetic traits of the individual organism.
While other fruits are soft and just as easy to pulverize, strawberries are the perfect choice for a DNA extraction lab for two very good reasons: (1) they yield way more DNA than other fruits, and (2) they are octoploid, meaning that they have eight copies of each type of DNA chromosome. (Human cells are generally diploid, meaning two sets of chromosomes.) These special circumstances make strawberry DNA both easy to extract and to see.
To extract the DNA, each component of the extraction mixture plays a part. Soap helps to dissolve cell membranes. Salt is added to release the DNA strands by breaking up protein chains that hold nucleic acids together. Finally, DNA is not soluble in isopropyl alcohol, especially when the alcohol is ice cold.