Growth factors are naturally occurring proteins that play a crucial role in regulating cellular processes, including cell growth, proliferation, and differentiation. They bind to specific receptors on the surface of cells, triggering a series of biochemical events that promote various functions essential for development and healing. These proteins are vital in many biological processes, such as wound healing and tissue repair. For example, platelet-derived growth factor (PDGF) is involved in blood vessel formation, while nerve growth factor (NGF) supports the survival and growth of neurons. Understanding growth factors is important in fields like medicine and biotechnology.