AP BIOLOGY

Detailed explanation-1: -Ligands that bind to RTKs include the fibroblast growth factors, epidermal growth factors, platelet-derived growth factors, and stem cell factor.

Detailed explanation-2: -One of these principles is the concept of amplification, i.e., the process by which activation of a relatively small number of G protein coupled receptors is transformed into a robust downstream signaling event.

Detailed explanation-3: -Ligands. The majority of signal transduction pathways involve the binding of signaling molecules, known as ligands, to receptors that trigger events inside the cell. The binding of a signaling molecule with a receptor causes a change in the conformation of the receptor, known as receptor activation.