What is meant by signal amplification during cell signaling?
a. There are multiple steps involving enzymes, each of which can activate multiple substrate molecules.
b. The first messenger activates the production of effector molecules which accumulate within the cell.
c. One signaling molecule can phosphorylate several receptors, activating all of them and increasing the signal to the cell.
d. Often an activated receptor can, in turn, activate other receptors, much like the opening of gated ion channels during the nerve impulse.