When a signal is initiated by the binding of an extracellular ligand, what is the immediate outcome of that signal?
A)A protein in the middle of an intracellular signaling pathway is activated.
B)A protein at the top of an intracellular signaling pathway is activated.
C)A protein at the top of an extracellular signaling pathway is activated.
D)A protein at the top of an intracellular signaling pathway is deactivated.
E)A protein at the bottom of an intracellular signaling pathway is activated.

Question

Quizplus · Accepted Answer

When an extracellular ligand binds, it typically activates a receptor protein at the top of an intracellular signaling pathway. This then triggers a cascade of events down the pathway, ultimately leading to a cellular response.

When a Signal Is Initiated by the Binding of an Extracellular