Put the isopropyl alcohol in the freezer. (This will be important that it is cold.)
Measure 6 tablespoons of water and add 2 teaspoons of dish soap and ¼ teaspoon of salt to the water. Stir the mixture together.
Put a strawberry in a plastic bag and put the water mixture into the bag. Remove as much air as possible from the bag when you seal it.
Mash up the strawberry until there are no big pieces left.
Pour the strawberry mush through a strainer to separate liquid from the solids. Then gently squish the solids through the strainer to get more juice out. Transfer the liquid into a smaller beaker/ test tube.
Add 1 teaspoon of the iced isopropyl alcohol to the strawberry liquids and use your tweezers to take out the white film on top of the solution.
The white film is the strawberry’s DNA
Science Behind It
Every ingredient that was used in this experiment served a purpose. The dish soap dissolved the cell membrane which makes it easier to get the DNA and the salt helps to isolate the DNA. It does that by breaking up protein chains that holds the nucleic acids together (nucleic acids are a part of DNA). The isopropyl alcohol is used because DNA is not soluble (meaning it does not dissolve in that) in it, which means that DNA will go to the top. The reason why this experiment works the best with strawberries is that they are easy to mush, have more DNA than other fruits, and they have 8 copies of each DNA chromosome (making them octoploid organisms), which makes that DNA bigger when you extract it. Humans are diploid organisms, meaning they have 2 copies of each chromosome and it also means that it is harder to see extracted DNA with the naked eye.
DNA stands for deoxyribonucleic acid. Every living organism contains DNA in every one of their cells. DNA makes up all of your physicals characteristics. It will determine what color hair you have, how tall you will be, and anything that makes you look like you. It also contains the instructions for life.
Chromosomes house the DNA and are made up of nucleic acids and proteins. Humans contain 23 pairs of chromosomes. Each chromosome has 2 base pairs, one from your mother and one from your father, giving you a total of 46 base pairs.
Tips
Members can try this with other fruits and vegetables. However, strawberries will work the best as their DNA is the largest and strawberries are easy to mash up.