02.16.2017
Written By: Whitney Wenger
Today we extracted DNA! After a quick review of some of the experiments we did last semester, we talked about different types of cells that keep us (and plants and animals) alive, talking also about how the different cells had different appearances based on their function. We talked about how small these cells are — comparing the size of a human cell to that of a human’s size is like comparing the size of a flea to the length of a football field. But do all cells look like the ones we saw in the presentation? Could we also extract DNA and look at that, too?
Although this experiment had two parts – DNA extraction and observation of cells under microscopes, most of the students had too much fun doing DNA extraction to spend much time looking at the cells under the microscope (in the future, I’d suggest doing this first before extraction to start the conversation). The students took their pick of strawberries, kiwis, spinach, and peas from which to attempt to extract DNA. While the peas and spinach were tougher to extract meaningful amounts of DNA from, the strawberries and kiwis yielded enough DNA to scoop up with a popsicle stick. The students enjoyed this part of the experiment and many experimented with a second fruit or vegetable to see how much DNA they could extract in comparison to their first test subjects.
This seemed to be a popular demo – even some of the quieter students seemed to really enjoy the hands-on nature of smashing fruits and vegetables. We discussed how scientists might study DNA to understand more about a certain species, and talked about how you could look at genetics of fruit and vegetables to develop better crops or even create hybrid crops (have you ever tried a Grapple?). Overall, the students seemed to enjoy this experiment.