Membranes are ubiquitous in living cells but many questions remain outstanding. These include how to characterize a membrane's material properties and their interactions with the environment. Living membranes are generically out of equilibrium and I will discuss how active fluctutations may be involved in the control of the formation of protein assemblies. These structures have important implications on the organization of cells within tissues and the control of their shape. I will outline basic physical principles which may contribute used to understand the epithelium. In the last part of the talk, I will outline the role of elasticity in the behavior of active swimmers, from a single entity to a swarm.