Phosphorylation

The addition of phosphate to an organic compound such as protein through the action of the enzyme phosphylase that triggers the glycogen molecule to form glucose.  It can change the activity of protein and is probably the most common mechanism for altering the biological function of proteins in cells and thus for transferring energy between cells. 

See Adenosine triphosphate (ATP), Creatine, Dephosphorylation, Enzyme, Glycogen, Krebs cycle ((or tri-carboxylic acid, TCA, cycle), Phosphate, Polymerization, Protein tyrosine kinase, Proteins