LINDEN – Linden High School science teaching team Andrew Grygo and Toni Scocchio recently prepared students for a DNA extraction lab.
The students first used Gatorade to “scrub” their cheeks of their skin cells. Prior to the lab, Mrs. Scocchio created an extraction buffer, which was a solution of water, detergent, and salt. The extraction buffer was added to the cells and mixed. The detergent broke down the cellular and nuclear membranes to allow the DNA (housed in the nucleus of cells) to be “free.” The salt helped to “stick” all of the newly-freed DNA strands together, making it easier for the students to see a larger strand of DNA.
Lastly the students add a small amount of cold isopropyl alcohol. DNA is not soluble in the alcohol so it precipitates. The students were immediately able to pull a stand of stringy DNA out of their containers. They then created a wet mount slide of their DNA and examined it under the compound light microscopes. The strands are too small to really see the actual components of DNA, however, the students appreciated the complexity of the activity.
Lauren Samuel prepares her compound microscope before observing her DNA extraction. (Photo by Linden High School/ Kate-Lynn Walker)
Patryk Zakrzewski sits at his desk adding an extraction buffer to his cheek cells before heading over to the microscope with a sample of his DNA. (Photo by Linden High School/ Kate-Lynn Walker)
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