Does a ligand bind to a receptor?

Yes, a ligand binds to a receptor. Ligands or signaling molecules are chemical messengers transmitted by cells to transmit signals to other cells or to itself. Receptors or receiving molecules are proteins that are found inside or outside the cell. When a ligand binds to a receptor on a target cell, the receptor’s conformation undergoes a change, initiating a complex signaling pathway inside of the cell. 

The ligand-receptor binding plays an integral role in several biological processes including neurotransmission, metabolism, and cellular signal transduction pathways. One ligand is capable of binding to several different receptors on different cells, resulting in different downstream effects.