What is the difference between a ligand and a receptor? Give an example. Solution Answer: A ligand is a biological molecule that binds to another molecule.Ex. Hormones and neurotransmitters. A receptor is a protein to which a signalling molecule (such as a neurotransmitter, drug, or hormone) binds specifically and stimulates a particular response by a cell. Ex. A hormone binding to a receptor. Oxygen binding (ligand) to haemoglobin (receptor). Antibodies (ligand) binding to antigens (receptor)..