Calcium Ions Can Serve as Second Messengers in Signal Transduction

Multiple Choice

Calcium ions can serve as second messengers in signal transduction pathways.Mechanisms in the cell can regulate calcium signals that have been activated during a signal transduction pathway.Which is a calcium regulation mechanism by which the cell returns to the state it was in before the pathway was initiated?

A) A protein binds calcium.
B) An enzyme is activated that degrades calcium ions.
C) Ion pumps move calcium ions into intracellular compartments.
D) Expression of the genes encoding calcium ion channel proteins is halted.
E) The concentration of activating molecules that open calcium ion channels is increased.