21 May, 2010

Crack the Code

Photo courtesy of all-about-forensic-science.com
Yesterday, scientists from the J. Craig Ventner Institute in the United States published a study in which  synthetic (or man-made) DNA "grew" for the first time. DNA is the abbreviation for deoxyribonucleic acid. Simply, it is the life code stored in the cell nucleus of living organisms. It forms the shape of a double helix, which looks kind of like a spiral shaped ladder. On the rungs of this ladder are four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). The order of these letters (A, G, C, and T) gives the information that form and sustain the organism. DNA has an important job to do. It replicates, or makes copies of itself. This replication is essential when cells divide, for each cell must carry the exact same code. For today's literacy activity, we will extract DNA from a strawberry. 

Here's what you need:
  • strawberry
  • plastic bag (one that self-seals like a ziploc)
  • rubbing alcohol
  • dish soap
  • water
  • small container with lid (I used an old spice jar)
Okay. So here's what you do:
  • Put the strawberry in the plastic bag and seal it. Smoosh it. Smoosh it all up. This takes about 3 minutes. (This is definitely the kid part of the experiment)
  • In the jar, fill half with water, and half with rubbing alcohol. Leave some room at the top. 
  • Add a very small drop of dish soap (especially if the soap is concentrated).Put the lid on the jar.
  • Shake it. Shake it real good. (This is another kid part)
  • So, now put your jar on the table and let it settle down.
  • Gaze into your jar. See all of those long, white slimy bits? (They are easy to see , but  so hard to photograph!)That is the strawberry's DNA!
Click here for an interactive website about DNA and here for more information about DNA and genetics. 
Click here to read about the recent synthetic DNA study. 

Special thanks to University of Miami Department of Neuroscience for teaching my kids and me how to do this fun experiment.

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