Cell signaling pathways are complex networks of interactions that allow cells to communicate with each other and respond to their environment. These pathways involve various molecules, such as hormones, proteins, and receptors, which transmit signals from the cell surface to its interior. This communication is essential for processes like growth, immune responses, and metabolism. When a signaling molecule binds to a receptor on a cell's surface, it triggers a series of biochemical reactions inside the cell. These reactions often involve second messengers, which amplify the signal and lead to specific cellular responses, such as gene expression or changes in cell behavior. Understanding these pathways is crucial for developing treatments for various diseases.