Chapter 11, Problem 2IQ

Summary Introduction

To explain: The reason why G protein-coupled receptor pathways shut down rapidly in the absence of a signal molecule.

Introduction: Signaling molecules are chemical substances such as hormones or growth factors that bind to specific receptors on cell membranes. These signaling molecules are involved in inducing important signal transduction pathways inside a cell. After a signal binds to the receptor, the receptor undergoes conformational changes in its structure and these changes are essential to activate various secondary messengers and enzymes to continue the signaling pathway. G protein-coupled receptors (GPCR) are one such protein receptors which are  responsible for activating several biologically significant signaling pathways in eukaryotes.