Cellular signals are the messages that cells use to communicate with each other. These signals can be chemical, like hormones, or electrical, like nerve impulses. They help cells respond to their environment, coordinate activities, and maintain homeostasis, which is the balance necessary for survival. When a cell receives a signal, it can trigger a response, such as growth, movement, or changes in metabolism. This process often involves specific receptors on the cell's surface that bind to the signaling molecules. Understanding cellular signals is crucial in fields like medicine and biotechnology, as it can lead to new treatments for diseases.