A first messenger is an extracellular messenger that binds to its receptor on the_______of the cell and therefore activates a second messenger system.

Question

Quizplus · Accepted Answer

First messengers are extracellular signals (like hormones or neurotransmitters) that bind to receptors on the outside surface of a cell, initiating a cascade of intracellular events that lead to a cellular response.

A First Messenger Is an Extracellular Messenger That Binds to Its