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Strawberry DNA Extraction Lab

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Presentation on theme: "Strawberry DNA Extraction Lab"— Presentation transcript:

1 Strawberry DNA Extraction Lab
S7L3.a Goals and Objectives: Students will understand that cells contain DNA. DNA is a physical structure that can be seen with an unaided eye. Students will prepare a solution containing strawberry DNA, and then precipitate the DNA to make it visible. Students will compare the DNA samples from others in the class and observe that DNA at this level looks the same no matter where it came from.

2 Strawberry DNA Extraction Lab
S7L3.a Vocabulary: DNA (deoxyribonucleic acid)—the molecule that contains all of the information for life; it contains all of the instructions for the physical and functional characteristics of an organism; it is contained in the nucleus of cells Interface - the place where the strawberry solution and the alcohol meet. Precipitate - to form a solid, DNA forms a solid when it comes into contact with the alcohol.

3 Strawberry DNA Extraction Lab
S7L3.a Background Information: For most people, DNA is a very abstract and difficult concept. This activity will bring about a better understanding that DNA is a physical substance found in the cells of living things. In this activity, students will add various solutions to strawberries to extract and visualize its DNA. The salt and the detergent solutions work together to break open the membranes of cells and their nuclei. The solutions also provide a medium in which the DNA remains dissolved. When alcohol is added to the solution, strands of DNA become tightly coiled together, producing a visible mass of DNA. This is DNA from thousands of cells. Once all of the DNA is out of the solution, the precipitated DNA will rise to the top of the alcohol.

4 Strawberry DNA Extraction

5 Strawberry DNA Extraction Lab
S7L3.a DNA Extraction 1. Get a small, heavy-duty zip-lock bag with a strawberry from your teacher. 2. Seal the bag and mash the strawberry thoroughly for 1 minute. 3. Add 10 ml (approx. two teaspoons) of DNA extraction buffer to the bag. 4. Seal the bag and mash again for 1 minute. Place a coffee filter over a cup and pour the strawberry mash through the coffee filter into the cup. 5. Fill the cup to approximately 1/8 full with the filtered liquid. (you may have to softly squeeze the filter to maximize the amount of extract that is collected. Be careful to not burst the filter!) 6. Slowly add the ice-cold alcohol so that it forms a layer on top of the filtered liquid until the cup is about ½ full. - The DNA will precipitate at the border between the alcohol and the filtered extract liquid. 7. The DNA can be spooled around a glass rod, pipette tip, straw. 8. Throw away all extract, bags, and cups. Clean up lab area. 9. Complete Exit Ticket #18: DNA Extraction Lab Analysis Questions. Place in Interactive Notebook when complete.

6 Lab Analysis Questions
1. What purpose is served by the Dawn dishwashing detergent? 2. Describe what the DNA looks like with your naked eye. 3. Where did the DNA first appear? 4. What might have happened if the alcohol was poured too fast and it did not form a layer on top of the water? 5. There is about 6 feet of DNA contained in each of your cells. How is it possible for so much DNA to fit inside the small space of a cell?


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