Cheek Cell DNA Extraction

Our second lab of the year is designed to teach us about our DNA. In the lab we will actually extract our own DNA and put in a bottle to attach to a necklace!

DNA is present in all living things, it is the "carrier of all genetic information" and it determines everything about you. It also carries instructions to tell your cells what to do, and how to do it. In this lab our goal is to precipitate the DNA in order to be able to see it by itself, and therefore futher our understanding of this tiny thing that has quite a bit of power over our bodies. From what we know from scientists, DNA is in the form of a twisted stairway type of structure. The each "step" of the stairway is made up of bases, there are four of them named, adenine, guanine, thymine, and cytosine. Each of the bases is connected to one sugar and a phosphate group, the full grouping of a base, sugar and phosphates, create the backbone of the DNA. The bases are organized so that they each base pairs up with one other base, adenine with thymine, and cytosine with guanine. The reason for the matching of the bases are because they make messages that can be understood by genes (inside the cell), and then the genes send the information to the proteins which control the basis for the body's structure and function.  

In this lab, the first step we will be taking is we will loosen our cheek cells by chewing on our cheeks, then we will use a saline solution (0.9 % salt water) to swish around our mouths, after 30 seconds we will replace the contaminated water back into the cup in order to create a funnel into a test tube to consolidate our salt water now ridden with cheek cells. The reason for using saline solution is to neutralize the DNA and make it hydrophobic (water-hating). Next we will add a lysis buffer to break down or dissolve the cell membranes in our cells, and then we will add 100 mL of protease to break down the proteins. After those steps we gently invert our test tubes, to mix up the solution. In addition to all these chemicals, next, we will put our text tubes in a water bath of about 50 degrees celsius for ten minutes to speed up the reaction. The last thing we will do is add 5 mL of cold ethanol. After doing this procedure, we should be able to see our DNA consolidated in the center of our test tube, revealing the most important piece of genetic makeup for our body!