Introduction:
a) Background:
In this lab, we extracted a cell from inside of our cheek and extracted its DNA. DNA, Deoxyribose Nucleic Acid, carries genetic information and determines one's features. It holds the information that is necessary for cells to carry out functions. DNA can be called a "biological blueprint" because it holds the information that creates the organism. DNA's structure is a double helix with 4 bases. Each base connects with a phosphate group and a sugar, forming the backbones of the DNA. DNA holds all of the information regarding your genes.
b) Purpose:
The purpose of this lab was to precipitate DNA. Precipitating DNA will allow us to compare DNA of different organisms, to map and sequence it, and to use it for other experiments, such as cloning. DNA in the precipitated form can help scientists in many areas. It can also text for diseases, show certain traits, and help determine one's identity in a crime scene.
c) Procedure:
First, we loosened our cheek cells. We used a saline solution, also called "iso tonic" that was 0.9% salt water, and this solution helped to ensure that the cheek cells were in the right concentration. We then added a lysis buffer, which would burst the cells open by dissolving the cell membranes). The cell membrane consists of fats, and the lysis buffer dissolves phospholipids. The cell membrane is hydrophobic, so it needs detergent to break it apart. Next, we added protease. Protease is an enzyme that breaks down protein. It left the DNA intact, and we were able to extract the DNA alone. After adding the enzyme, we placed the vile into a hot water bath. The hot water speeds up the reaction and helps to break up the cell membrane. After placing it in the heat for 10 minutes, we added cold ethanol to help with the precipitation process. DNA has a negative charge and the phosphates are also negative and have to be on the outside of the structure. When dropped into water, DNA dissolves, so to precipitate it, we add salt. NA+ neutralizes the charge and makes DNA nonpolar, so that it does not break up in the water and it stays intact.
Summary/Results/Possible Sources of Error:
I was able to extract my DNA and place it into a small vile. The vile was attached to a necklace. While doing the lab, I learned about the process to precipitate DNA. The process was straightforward and easy to follow, and I understand the reason why we did all of the steps. The lab results could have been skewed because it was possible for one to put the vile in the hot water for not enough time. This would cause the reaction to take place more slowly and the cell membrane would have trouble breaking up. Also, if I did not add salt, the DNA would have dissolved.
