Peripheral membrane proteins are proteins that are attached to the surface of cell membranes but do not penetrate the lipid bilayer. They can associate with the membrane through interactions with integral membrane proteins or by binding to the polar heads of lipids. These proteins play crucial roles in various cellular functions, including signaling, maintaining the cell's shape, and facilitating communication between the cell and its environment. Unlike integral membrane proteins, which span the membrane, peripheral membrane proteins can be easily removed without disrupting the membrane structure. They often participate in dynamic processes, such as cell signaling and cell adhesion, and can be found in various cellular compartments, contributing to the overall functionality of the cell.