DNA, test tube.
For this project, we were required to take clear test tube, as well as a few other ingredients, and attempt to isolate our DNA. In order to begin the process, we were required to retrieve live cell's floating around mouth. In order to do so, we took our tongues, and rubbed them on the checks of our mouths, doing this took the live cell's that were lining our checks and un isolated them. Once we were done with this step we were required to take the clear test tube and spit into it. Once our spit was lying still at the bottom of the tube, we took blue dish soap, and forced it into the test tube. Although this process sounds easy it intact was the most difficult part. When we put the dish soap into the test tube, it had to hit the bare bottom. If it didn't hit the bare bottom, there was only one other possibility. The soap that was being squeezed out would stick to the sides, and contaminate the rest of the DNA. Once I completed this step, which wasn't right away, I moved on to the rest. After we spit into the test tube and managed get the shop perfectly on the bottom, we then added a table spoon of salt and two table spoons of ruling alcohol. Once these steps were complete, the process to isolating our DNA, was not complete. Time. Time was the last ingredient, the one ingredient that could make or brake the project. Luckily enough I was able to insert the ingredients to my standards, and time it perfectly, which resulted in a clear, but not perfect version of my isolated DNA. Here is photo of my DNA in the end.
What am I looking at?
Now at this point, I'm sure that you are looking at this and saying "what am I looking at". Give me a moment and you will be informed. What you are looking at is general sample of one "my" DNA. So basically what this is, and or how to tell what is, is very simple. The yellowish kind of caramel like color at the bottom of the test tube, is the dish soap, then one step up there is a little line. This line is basically a barrier for the soap and the spit "saliva". The reason why this barrier is there, is because the salvia and dish soap are made of two chemically different properties. The dish soap is made up of two compounds, the Carboxylic acid group and the Hydrocarbon chain. What happens when these two substances are intertwined, is what makes dish soap different from the rest. When these two compunds are mixed together it creates whats called the fatty acid group. The fatty acid group is what allows dish soap to clean, and remove other substances so well. Now I'm sure you are thinking that because the fatty acid in dish soap, dish soap should be able to intertwine and absorb any substance. But that is unfortunately wrong. The acid that is in our spit, prevents the dish soap to soak into the saliva. Which is why there is that small white barrier between the two.
This is the way many scientists extract DNA.
- Break open (lyse) the cells or virus containing the DNA of interest-
This is often done by sonicating or bead beating the sample. Vortexing with phenol (sometimes heated) is often effective for breaking down protienacious cellular walls or viral capsids. The addition of a detergent such as SDS is often necessary to remove lipid membranes. - DNA associated proteins, as well as other cellular proteins, may be degraded with the addition of a protease. Precipitation of the protein is aided by the addition of a salt such as ammonium or sodium acetate. When the sample is vortexed with phenol-chloroform and centrifuged the proteins will remain in the organic phase and can be drawn off carefully. The DNA will be found at the interface between the two phases.
- DNA is the precipitated by mixing with cold ethanol or isopropanol and then centrifuging. The DNA is insoluble in the alcohol and will come out of solution, and the alcohol serves as a wash to remove the salt previously added.
- Wash the resultant DNA pellet with cold alcohol again and centrifuge for retrieval of the pellet.
- After pouring the alcohol off the pellet and drying, the DNA can be re-suspended in a buffer such as Tris or TE.
- Presence of DNA can be confirmed by electrophoresing on an agarose gel containing ethidium bromide, or another fluorescent dye that reacts with the DNA, and checking under UV light.
-SERC Science Education Research Center.
This is often done by sonicating or bead beating the sample. Vortexing with phenol (sometimes heated) is often effective for breaking down protienacious cellular walls or viral capsids. The addition of a detergent such as SDS is often necessary to remove lipid membranes.