DNA Extraction Lab Conclusion

In this lab, we asked the question, "How can DNA be separated from cheek cells in order to study it?" This lab was different from the rest, however. Instead of following the steps of the lab and getting the end result, we actually had to organize the procedure into the correct steps in order to achieve the desired results. We first scraped cheek cells from the inside of our cheeks. Then, we swished them around in a small amount of Gatorade, and spit the solution into a cup. After that, we poured the solution into a test tube and mixed it in with a small amount of salt, and about 9 drops of both Dawn Dish Soap and Pineapple Juice. The salt facilitated the precipitation, which allowed the ends of the DNA to move closer together. The dish soap was used to lyse the solution, or disintegrate the cell wall/membrane and get to the DNA. Finally, the Pineapple Juice acted as the enzyme which helped break down any remaining proteins, called histones, which the DNA molecule wraps itself around.  After this, we shook the test tube containing the newly made solution, and waited for about 5 minutes for the solution to mix and settle. After the 5 minutes, we added cold isopropanol alcohol in such a way that the Gatorade solution and the alcohol don't mix. This would lead to an unwanted result. The alcohol itself is non polar, while the DNA is polar, which leads to the DNA falling out or separating at the interface of the two solutions. We found that by following the procedure stated above as closely as possible, and by being especially careful while handling such solutions as the alcohol or Gatorade solution with everything mixed in can help attain the desired results.

This photo shows the procedure we organized

At first when we added the salt, soap, and juice to the Gatorade solution in the test tube and gently mixed it, the solution was a rather still translucent red. You could begin to see the cheek cells inside the solution. They looked like small white specks connected/bunched together to make thin, fibrous strands. However, after we added the alcohol, we could start to see a haze in between the two solutions. This was the slow precipitation of the DNA extraction. Soon after the white haze had formed, small chunks of DNA started to separate and become visible in the alcohol solution.

 This is the Gatorade solution and the alcohol in the test tube and the start of the precipitation process.

While our hypothesis was supported by our data, there could have been errors in my test tube and experiment especially because of the amount of solution that ended up in my test tube. From my table group's results and my own results, I can conclude that the amount of the Gatorade solution, and the alcohol which had to have a similar result, does affect the time the precipitation process takes. One table partner had used very little of both solutions, a little less than one third, and this lead to a large amount of DNA extracted from the solution in a short amount of time. However, I created an end solution that filled the test tube. This lead to an extremely slow precipitation process and the small amount of DNA extracted from the process. Another possible error could be the soap bubbles created due to the speed and intesity of the shaking of the solution before we added the alcohol. The procedure specifically states shake the test tube in such a way that minimized the creation of soap bubbles. However, no matter how we shook the test tube, bubble always formed. I cannot say that this affected our results in a negative or positive way because we all tested the tube with the same procedure of shaking the tube. Due to these errors, in future experiments I would suggest the procedure be changed for two of the steps. First, it would minimize the risk of creating soap bubbles by using a device to stir the solution gently instead of shaking it. This could lead to more accurate results. Another step that would be more helpful to change would be the amount of Gatorade solution used in the test tube. I would suggest that the procedure only states 1/3 of the test tube should be filled up in order to speed up the process and create more DNA extraction. 

 This picture shows the soap bubbles formed from the shaking of the solution. 

This lab was done to demonstrate not only the isolation process of DNA, but also the functions and characteristics of DNA, homogenization, lysis, and precipitation. From this lab, I learned more about the characteristics of DNA, like the fact that it is polar. I also learned the functions of many factors used to isolate DNA, which helps me understand how scientists can isolate DNA and study it. It also helps me understand the concept of DNA itself.