DNA (from Strawberries!)

DNA is Everywhere! In this lesson students learned all about deoxyribonucleic acid, more commonly known as DNA. After getting a brief overview of DNA’s role in the storage of genetic information, students followed a DNA extraction protocol experiment and successfully extracted DNA from strawberries by breaking down the cell membranes with detergent, then freeing the DNA from its protective proteins (histones) by using a protease (an enzyme that breaks down protein – actually Accent Meat Tenderizer!). By breaking down the cell wall, membrane, and nuclear membrane, students were able to isolate the nucleic acids. They then added some very cold isopropyl alcohol to the resulting lysate (the fluid and cell remnants left over when the cells were broken up), which caused the DNA to become visible at the border between the aqueous solution and the alcohol. The addition of alcohol to the cell lysate allows the nucleic acids become visible without a microscope! The activity involved a number of different steps and helped emphasize the importance of following directions carefully. The young scientists were rewarded for their diligence by seeing DNA in their test cups at the end of the lab!

Author

Dr. Catherine Sukow

Dr. Sukow's interest in science education began when she was a teenager, with an extended visit to San Francisco's Exploratorium. In college, she had summer jobs in a similar, smaller, museum. She focused her Master's research at NCSU on the structure of metal silicides on silicon, and her Ph. D. work at Brandeis on the structure of crossbridged actin bundles. While volunteering in her childrens' schools, she was reminded how much fun it is to teach science, and is happy to be teaching now with Science from Scientists. In her spare time, she also enjoys yoga, choral and solo singing, and attempting a variety of international cuisines.

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