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, the students followed a DNA isolation protocol experiment and successfully extracted DNA from bananas 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 dribbled the resulting lysate (the fluid and cell remnants left over when the banana cells were broken up) through some very cold 70% ethanol, which caused the DNA to become visible at the border between the aqueous solution and the ethanol. The addition of ethanol 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 tubes at the end of the lab!
You can find out how to make DNA origami here!
A similar experiment for home use is described here: http://learn.genetics.utah.edu/content/labs/extraction/howto/DNA_Extraction.pdf