What does a ligand do in molecular interactions?

A ligand plays a crucial role in molecular interactions by binding specifically to a receptor site on another molecule. This binding mechanism is fundamental in various biological processes, including signal transduction, where the ligand's attachment to the receptor induces a conformational change in the receptor. This change can trigger a cascade of biological activities within the cell, allowing for communication and regulation of functions.

In many cases, ligands are hormones, neurotransmitters, or other signaling molecules that exert their effects by engaging specific receptors, facilitating processes such as metabolic regulation, immune responses, and cellular communication. The specificity of this binding is essential, as it ensures that each ligand only interacts with the appropriate receptor, leading to the desired biological response.