Previously, we have studied how and why biology works; how a complex collection of dead matter can give rise to life and all its processes. Now that we have begun to understand many of these complicated interactions, we can put them to use with synthetic biology. Synthetic biology combines the best of both biology and engineering in the design of new biological functions not ordinarily found in nature. This is done by modifying an organism's DNA, similar to how a computer scientist might modify the script for a computer program. This biological "programming" (or "re-programming") isn't done in quite the same way, however. Over the past years people have identified discrete blocks of DNA that code for something useful (proteins, enzymes, etc.) and have identified them as genes. By combining these useful chunks of DNA, we can build new sequences that code for something useful to us. Sometimes, we may just want to give an organism a function of another, but we may also build entirely new functions never seen before! With synthetic biology, the sky is the limit!