The biological activity of cellular membranes is mediated by an array of fascinating and highly specialised proteins embedded within the lipid bilayer. These proteins support essential functions such as sensing, signalling, transport and energy transduction and form the focus of this module. An introduction to the principles that govern the structure of these proteins is followed by a series of case studies that explore the link between protein structure, location and function that includes the following; aquaporins and water transport, bacteriorhodopsin and light driven proton movements and hypoxia signalling by mitochondrial proteins. NB students who do not have the pre-requisite module (BIO-2B01), but who have taken and passed BIO-1A13, BIO-1A61 and either BIO-2B06 or BIO-2B28 can take this module if they obtain the agreement of the module organiser.