Membrane proteins are essential components of cell membranes, playing crucial roles in various cellular functions. They can be classified into two main types: integral proteins, which are embedded within the membrane, and peripheral proteins, which are attached to the membrane's surface. These proteins help transport substances in and out of the cell, communicate signals, and maintain the cell's structure. Additionally, membrane proteins are involved in processes like cell signaling and immune response. For example, some membrane proteins act as receptors, allowing cells to respond to hormones or other signaling molecules. Their diverse functions make them vital for the overall health and operation of living organisms.