Ms. Ellen Hellerich Nebraska Agriculture in the Classroom Ms. Marsha Purcell American Farm Bureau Foundation for Agriculture Edited by Debra Spielmaker Utah Agriculture in the Classroom Edited by Mary Phillips Tulsa Community College

1.To provide students with an understanding that cells (and all living things) contain DNA 2. DNA is a physical structure that can be seen with an unaided eye

To prepare a solution containing their DNA. Precipitate their DNA to make it visible. 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.

DNA is found in the cells of all living things Students will be able to see their own DNA protein strands The soap and salt are added together to release the DNA strands from the cell membranes Alcohol is added to the solution to precipitate the DNA

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. water Very Cold Ethyl Alcohol (91% or greater, keep on ice) Eye Droppers or disposable pipettes Paper Towels for clean-up

1.Obtain and label a plastic cup with your name Erin Fay

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

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!

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

5. Add 1 ml/10 drops of detergent solution into your test 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

7. Add a pinch of salt

Gently rock (NOT SHAKE!) the test tube back and forth to mix the contents, so that bubbles do not form. Let it sit for approximately 5 min.

8. Add ice cold ethyl alcohol down the side of your test tube. Approximately, twice as much as cheek cell water. Do NOT add alcohol directly on your cheek cell solution. 91% ice cold alcohol- keep in the freezer and/or ice bath

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

Cauliflower and Sweetbread (Thymus gland) 1.Use approximately 1 -2 cauliflower pieces. 2.Place the cauliflower in a mortar and pestle and measure 10 ml of buffer solution (water, soap and salt) 3.Add buffer solution to your mortar and pestle. M. Phillips

4. Grind cauliflower (you may need to add additional buffer solution 1-5 ml) and allow to sit for 5-10 minutes. 5. Using a funnel and filter paper, filter approximately. You need approximately 1 cm (1/3 of your test tube) 6. Add twice the amount of alcohol.

EXTRACT DNA FROM PEAS 1.Measure 1 g of crushed dry peas (pre-blended) 2.Add 10 ml of hot tap water (approx C) 3.Use glass or wooden rod to mix for 3-5 min. 4.Add 2 ml of 30% soap solution (30 ml soap/70 ml water) 5.Gently shake – Make sure DNA source is not stuck on the sides of the test tube. 6.Let it sit for 3-5 minutes.

7. Add 5 ml of ice cold ethyl alcohol down the side of your test tube. 8. Let the test tube sit for approximately 10 minutes. 91% ice cold alcohol- keep in the freezer and/or ice bath

InterfaceInterface Precipitate

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

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

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