Ligand-receptor interactions are essential processes in cellular communication. A ligand is a molecule, such as a hormone or neurotransmitter, that binds to a specific receptor on the surface of a cell. This binding triggers a response within the cell, leading to various biological effects, such as changes in gene expression or cellular activity. These interactions are highly specific, meaning that each receptor typically binds to only one type of ligand. This specificity ensures that cells respond appropriately to different signals, allowing for precise regulation of physiological processes, including growth, immune responses, and metabolism.