Do receptor proteins bind only to signals that match the specific color of the binding site?

No, receptor proteins do not bind only to signals that match the specific "color" of the binding site; rather, they bind to specific molecules based on their shape and chemical properties. The binding site of a receptor has a unique structure that allows it to interact with certain ligands, which can be hormones, neurotransmitters, or other signaling molecules. This specificity is determined by molecular interactions such as hydrogen bonds, hydrophobic interactions, and ionic interactions, rather than color.