Molecular biology is the study of life processes on a small scale. As a whole organism is composed of cells, so are these cells composed of tightly regulated molecular machinery that keep them alive and functioning. Molecular biologists use chemical and biological tools to study DNA, RNA, proteins, and the interactions between them.

These tools have allowed scientists to have a far more detailed understanding of cellular processes than was imagined possible a century ago. One of the most groundbreaking developments in this field has been the polymerase chain reaction (PCR), first conceived by Kary B. Mullis in the 1970s. This technique, which uses DNA-copying polymerases derived from bacteria found in hot springs, can be used to isolate a tiny needle of DNA from a nucleic haystack and copy it many times over. Today, PCR is used in nearly every molecular biology lab to reproduce genes...