If a Signalling Molecule (Ligand) Triggers an Effect (Protein Phosphorylation)

Multiple Choice

If a signalling molecule (ligand) triggers an effect (protein phosphorylation) via a second messenger system, which will produce the greatest change in the magnitude of the effect in a target cell?

A) Adding one molecule of ligand to the cytoplasm of the cell.
B) Adding one molecule of ligand to the extracellular fluid surrounding the cell.
C) Adding one molecule of the second messenger to the cytoplasm of the cell.
D) Adding ATP to the cytoplasm of the cell.
E) Adding one molecule of activated protein kinase to the cytoplasm of the cell.