I propose to bridge the gap between simple in vitro measurements of biological processes, and the complexities of the cellular environment. This requires reduced in vitro systems that are sufficiently complex to reproduce the subtleties of the in vivo biological phenomenon, but sufficiently controllable to test how quantitative changes in a particular property affects function. The challenge is to step beyond the most simple and straightforward in vitro mimics of the cell membrane, and create model systems that more closely reproduce the conditions in vivo.I propose to tackle two specific, but interrelated membrane phenomena, that are currently not captured in artificial bilayers and create new complex mimics of the cell membrane capable of tackling these systems; namely (1) protein crowding and the cytoskeleton, and (2) lateral forces and membrane curvature. Testing our synthetic mimics with models that we understand in vivo is vital. This benchmarking will ensure that the mimics we create are relevant and will help ensure the more ambitious later goals of the this proposal are successful.We will then take these tools to go on and aim to create a synthetic mimic of the bacterial membrane.However we are not limited to creating purely natural duplicates, and we can exploit a much wider range of building material than nature. In addition to creating complex mimics, we will also create totally new synthetic systems inspired by the properties of the cell membrane, but possessing unique properties.