Extract DNA from Strawberries!

Living things need instructions on how to make the millions of complex molecules they use to survive and thrive.

Nucleic acids carry instructions that tell cells when and how to make the proteins they need to survive and grow.

Nucleic acids come in two kinds. You’ve probably heard of one kind: DNA! DNA stands for deoxyribonucleic acid.

A full copy of a living thing’s DNA is stored in the nucleus of each cell. A single strand of DNA can be made up of billions of atoms! If you stretched it out, it would be about 2 inches (5 centimeters) long!

DNA is a chemical that acts like the letters in the instruction booklet of life!

You can see what this amazing chemical of life looks like when you extract DNA from a strawberry!

What you need:

• Fresh or frozen strawberries – about one cup
• Zip-loc bag or a plastic bag that can be closed and sealed
• Rubbing alcohol
• Water
• Dish washing liquid
• Toothpicks
• Coffee filters
• Clear Drinking glass
• Salt

Instructions:

1. First place the rubbing alcohol in a freezer. This works best when the alcohol is cold. Place about 1/3 cup of fresh or thawed frozen strawberries in a plastic bag. Use your hands to mash the berries into a pulp.
2. Mix 1/2 cup of water with 2 teaspoons of dish soap and ½ teaspoon of salt in a glass. Try to mix these ingredients and stir carefully—you don’t want to make a lot of bubbles!
3. Add this mixture to the plastic bag of mashed berries. Use your hands to mash the mixture more. Then, after it is fully mixed, use your hands to squeeze out any air and tightly seal the bag.
4. Allow this mixture to sit for at least 15 minutes. Longer is better.
5. Now you need to filter your mixture. Place a coffee filter over a glass and pour the mixture into the filter. Let the juice filter into the glass. Start by filtering small amounts at first. This may take several filters. Get as much juice into the glass as you can. Once you have the juice, you can throw away the remaining fruit mash.
6. Now slowly pour some cold rubbing alcohol down the side of the glass. You want to pour carefully, so the alcohol forms a clear layer over the strawberry juice. Let the alcohol sit for a time on the juice. You will start to see a stringy white material form where the alcohol meets the juice.
7. Use a toothpick to collect and remove the stringy white material that has formed on the juice.

This stringy white material is millions of tiny strands of DNA from the fruit!

You can remove the DNA with the toothpicks and even store it in a container full of rubbing alcohol.

Now, read about the DNA molecule and what it does.