Wind Your Way Around Your Own DNA! Original by: Ms. Marsha Purcell American Farm Bureau Foundation for Agriculture Managing Director Ms. Ellen Hellerich Nebraska Agriculture In The Classroom State Coordinator Modified by Georgia Agriculture Education Curriculum Office –June 2004

Learning Goals To provide students with an understanding that cells contain DNA! DNA is a physical structure that can be seen with an unaided eye!

Student Objectives 2. To prepare a solution containing their DNA! 1. Precipitate their DNA to make it visible! 3. Compare the DNA samples from others in the class to see that at this level, DNA looks the same no matter where it comes from!

Getting Started! DNA is found in the cells of all living things! DNA is a very abstract and difficult concept! DNA is found in the cells of all living things! Students will be able to visualize their own DNA! The solutions work together to break open the cell membranes, therefore releasing the DNA! Alcohol is added to the solution to precipitate the DNA!

What do you need? Distilled/Bottled Water 3 oz. Plastic Cup Small test tube w/cap or plastic tube w/lid from a florist 1 Tsp. dish soap/shampoo mixed with 3 Tsp. water 1 Tsp. Gatorade Cold Ethyl Alcohol (91% or greater) Eye Droppers or disposable pipettes Paper Towels for clean-up J

J Let's see some DNA! Obtain and label a plastic cup with your name Erin Fay J

J 2. Fill your cup with approximately 5 ml/1 Teaspoon of Gatorade Erin Fay J

3. Swish the water in your mouth for no less than 30 seconds then return your “cheek water” to your cup! Remember to rub your tongue on the inside surface of your cheeks to help dislodge more cells!

J 4. Slowly pour enough “cheek water” to make the test tube half full. Erin Fay J

5. Add 1 ml/10 drops of detergent solution into your test tube and cap the tube.

6. Gently rock (NOT SHAKE!) the test tube back and forth to mix the contents, so that bubbles do not form.

No Bubbles? Great! Remove the cap and keep the test tube upright from this point on! Ellen

8. Add 5 ml/1 Teaspoon of ice cold ethyl alcohol 8. Add 5 ml/1 Teaspoon of ice cold ethyl alcohol. This should almost fill the test tube.

9. Observe the interface for the precipitation of the DNA 9. Observe the interface for the precipitation of the DNA. Small bubbles with white strings attached will slowly make their way to the top of the alcohol. This is DNA!

10. Pour contents of test tube back into plastic cup and dispose of the materials as directed. “Super Intern” Erin Fay J

Interface Precipitate Key Terms Interface Precipitate

Discussion ? ? ? ? Did everyone’s DNA look the same? Why did some people have more DNA? ? What would have happened if you had been chewing gum? ?

What some more IDEAS? Try using warm water to bathe the test tube until it is 55°C! What other organisms can you extract DNA from? Experiment w/different concentrations of Gatorade/detergent! Try different swishing methods!

References St. Louis Science Center UIUC – Hughes Biotechnology Education and Outreach Program