The polymerase chain reaction (PCR) is a process of gene amlification. First, a select gene is cut using restriction enzymes, then a comlementary strand is made and placed in a vial of polymerase and nucleotides like uracil, guanine, cytosine, thymine, and adenine. It assembles itself to millions of copies of genes (DNA fragments) that can be used in multiple situations: multiplying a cell product in order to mass roduce; amlifying gene proteins and enzymes; as well as for experiments carried on the lab.