Human DNA Extraction Lab Conclusion

In this lab, we asked how DNA can be separated from cheek cells in order for it to be seen and studied? We found that in order to extract DNA from cheek cells, three steps must be followed: homogenization, lysis, and precipitation. We accomplished this by homogenizing the cell's tissue with polar liquid. This breaks down the cell membrane and nuclear membrane of the cheek cell. We scraped off some of our cheek cells with our teeth, then swiveled it around in our mouths for 30 seconds. Afterwards we added soap, which was involved in lysis (the disintegration of the cell membrane). We used pineapple juice to break down histones found in DNA that the DNA wraps itself around. This is because pineapple juice, like a few other liquids, has catabolic proteases, enzymes, that help to break down the histones. Then we poured cold isopropanol alchohol onto the test tube and due to the nonpolarity and the polarity of the DNA the DNA became a precipitate and rose to the top of the isopropanol alchohol layer. This data support our claim because in order for DNA inside the nucleus to be seen, first the cell membranes, plasma membranes, and nuclear material must be broken down.

While our hypothesis was supported by our data, there could have been possible errors due to gargling the Gatorade for less than exactly 30 seconds. This would have affected the experiment in that all of the cheek cells would not have been caught in the solution. Also when we left the test tubes in the rack for observation, we did not time the 5 minutes exactly and this may have not allowed the solution to settle enough. I think our group should have used timers for both the gargling of Gatorade and the test tube 5 minute observation to make the experiment more accurate.

This lab was done to demonstrate our understanding of DNA and the process of extracting DNA out of a cell. From this lab I was able to understand how DNA is located in the cell, and that all the membranes that must be broken down differently in order to see the DNA. Based on my experience in this lab, I can apply this same process to extracting DNA from any cells and understand how the process works.