Biological_B3-3

Dennis Bray

Protein networks versus microchips

Cells are built up of molecular circuits that perform logical operations, analogous in many ways to electronic devices but with unique properties. Proteins and other molecules act like miniature transistors to guide the biochemical processes of a cell; linked into huge networks they form the basis of all of the distinctive properties of living systems. However, as illustrated by our work on bacterial chemotaxis, the simple form of behaviour in which bacteria smell and swim towards distant sources of food, living circuitry differs in fundamental respects to silicon devices. It has unique features such as a highly malleable internal architecture and an existence of a multitude of molecular states that

we cannot yet resolve or reproduce. Moreover, the same uncertainty exists for any process in any organism and is especially pronounced in higher animals such as humans. The myriad molecular states available to living cells confer features such as individuality and responsiveness to the environment. They are vital for the survival of the organism but cannot at present be replicated on a computer.
 
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