Science Cafe 2/5/18

Wetware: A computer in every living cell by Dennis Bray

This week we had an interesting talk from Professor Dennis Bray from Cambridge University. His talk revolved around the subject of astounding behaviour within the simplest of living organisms, single-celled amoeba and bacteria. He explains how proteins are the key for these organisms to displaying traits such as memory capacity, trial and error and problem

solving, despite not having a nervous system or structures as complicated as a human being. For example Stentor , a single celled amoeba which feeds on particles from its direct surrounding, is able to use different methods in order to prevent toxic chemicals like carmine from entering its mouth cavity. In its efforts to avoid carmine Stentor uses different methods such as blowing carmine away from its mouth cavity or turning its cavity in the opposite direction of the carmine. For Stentor to be able to display such trial and error, it uses different proteins to choose how to act. Some of the most important of these proteins are enzymes, specifically allosteric enzymes which have two active sites, allowing one enzyme to perform two separate functions. With allosteric enzymes, a simple organism has the ability to regulate its actions in order to act appropriately and beneficially to its situation. Due to evolution, these organisms are able to compute their situation without eyes or a brain and with complicated mechanisms using proteins, have survived to this day.