Kinases and phosphatases are essential to the cell because they:

a) Are enzymes that synthesize proteins.

b) Are enzymes that degrade proteins.

c) Are enzymes that can turn proteins “on” and/or “off” through changes in phosphorylation.

d) Are enzymes that can turn proteins “on” and/or “off” through changes in proton concentrations.

e) None of the above.