Cherry DNA Activity

Cherry DNA Lab


What is this about? - DNA is the chemical that makes up your genetic code. Although DNA is in every cell of your body, you probably have never seen DNA. This experiment makes the invisible visible.

Genomic Basics: DNA Extraction is at the heart of biotechnology. One of the first steps that biologists perform in the quest to identify a gene, learn the function of a particular protein, or identify the perpetrator of a violent crime is to isolate the genetic material. The fibers of DNA store the information for the functioning of the chemistry of life. A single unbroken strand can contain millions of atoms. Once DNA fragments are released into solution, the DNA can be spooled together by using ice-cold alcohol. When the alcohol is added, the DNA clumps together and precipitates at the water/alcohol interface because the DNA is not soluble in alcohol.


Safety Notes: Wash your hands before and after the activity and wear goggles when using the alcohol


Let’s make a Hypothesis...or...What Questions come to mind?

1. Would you be able to extract DNA
from animal cells using these methods?

2. What does the DNA look like?
Describe its texture and color.

3. Why does adding the alcohol
enable you to see the DNA?

Directions

Activity Time:
15 minutes

What You Need:
. Salt or meat tenderizer
. Liquid Detergent (Woolite) or liquid hand soap (Ivory) or any clear soap
. Water
. Cherries either fresh or frozen NOT canned
. Coffee filter or paper towel
. Funnel
. Alcohol/Ethanol (at least 90%) - cold - 91% isopropyl is available at Giant
. Small test tubes or any other small clear container like a medicine cup
. Plastic zip lock bag sandwich size
. Pencil or straightened paper clip

What to do?
1. Put the alcohol in the freezer or on ice.
2. Place 4 or 5 cherries in a plastic zip lock lunch bag - zip bag shut. If using fresh cherries, remove the pit.
3. Mash fruit well - This helps to break down the cell walls
4. In a container mix approximately 1 tablespoon detergent or hand soap (if using a pump container - two pumps) ¼ teaspoon of salt or meat tenderizer and a tablespoon of water
5. Add this mixture to the bag containing the mashed cherries.
6. Mix well
7. Using a funnel, filter the mixture into a test tube or other small clear container.
8. Remove funnel
9. While holding the tube at an angle, carefully layer cold alcohol over the cherry solution until you have twice as much alcohol as cherry solution. There will be a visible interface between the alcohol layer and cherry mixture layer. A slimy material will precipitate at the interface of the alcohol and filtrate layers. This material consists of clumped-together DNA strands and some protein. This is DNA.
10. Allow the tube or container to sit undisturbed for 5 minutes.
11. Using the paper clip hook or pencil, immerse to the depth of the interface, to spool up the DNA fibers. Use a slow twirling motion to avoid breaking and separating the strands.

For Further Information

http://biotech.biology.arizona.edu/
http://gslc.genetics.utah.edu/
http://www.nps.gov/