Biological systems are large assemblies of parts that function together following rules of basic chemistry. As systems, they can be studied, modified, and engineered for novel purposes. DNA molecules contain the information used to encode living systems, and methods exist for discovering and manipulating this information. This talk will cover the basic components of biological systems, including how DNA can be modified to make new proteins or genetically modified organisms, such as fluorescent mice, therapeutic viruses, or bacteria that eat explosives or smell like bananas.