DNA is the code that tells our body how to develop and function (“Understanding DNA”,Chris A Caladine,2004). The purpose of DNA extraction is to obtain DNA in a relatively purified form which can be used for further experiment such as PCR. DNA extraction also are very important in research process since it reduces the contaminants that may destroy the competency of the experiment result, and also it increases the shelf life of the sample. The basic technique for DNA extraction is lysing the cell by removing the contaminants from the nucleic acid (isolating the nucleic acid), and precipitating it in a buffer solution (Nuffield,2012). The buffer solution is the one who maintain the pH in a stable condition because DNA is pH sensitive. Any slight changes in the pH may contam or destroy the nucleic acid, and the most used buffer is Tris buffer (“What is The Function of Tris Buffer in DNA Extraction?” Scientific, 2015). In DNA extraction, cold ethanol are used because it separates the nucleic acid from the solution and it inactivate the enzyme that degrade the nucleic acid (“Ethanol Precipitation in DNA and RNA : How it works?” Biosize,2015). Nucleic acid are hydrophilic, which means it dissolves in water. But, nucleic acid are insoluble in ethanol, and if followed by centrifugation, the nucleic acid will come out of the solution, thus, white nucleic acid pellet will form. TE buffer also helps in DNA extraction because it has the ability to solubilize DNA or RNA, preventing it from degrading. PCR is a technique that are able to amplify small sections of DNA by going through repeatedly changed temperature so the copies that are produced cover the target region (Khan Academy,2016). The enzyme used in PCR is Taq Polymerase which make DNA of a target region if given primer. Three important steps of PCR are denaturation, annealing, and extension. PCR’s result can be seen through gel electrophoresis. It uses electric current to pull fragments of DNA through a special gel according to its size. And the size of the fragments can be determined by adding DNA ladder as a comparison. The gel that were used in gel electrophoresis was agarose gel because agarose gel has quite big pores that make the substances able to run through the gel. PCR is a breakthrough in science world since it is useful in so many field such as life sciences, medical sciences, and also in forensic sciences.