When synthetic biologists talk about what they are doing, they often point to the analogies between their work and what happens in engineering, particularly electronics engineering. You can point to some processes in living cells and describe them in the same terms as digital logic or oscillators - the kind of functions you find in a lot of electronic circuits.
The analogies don't stop there: the aim of synthetic biology is to develop a kit of parts from which you can build organic systems able to make fuels, drugs and chemical sensors. What are the parts? Professor Richard Kitney of Imperial College, London says: "We mean encoded biological functions: usually we mean modified bacterial DNA."
That modified DNA is injected into bacteria which has the machinery already in place to do the next bit, which is to make the parts work together to create simple circuits and, ultimately, create a system that does something. The annual iGEM competition, where undergraduate teams cook up modified bacteria to do unusual things, shows what can be done even at this stage.