Early work on signal transduction and glycogen metabolism by sutherland indicated that
a. the signal molecule combined directly with a cytosolic enzyme to form an active quaternary structure
b. the signal molecule worked equally well with intact or disrupted cells
c. the signal molecule did not interact directly with the cytosolic enzyme, but required an intact plasma membrane before the enzyme could be activated
d. the cell-signaling pathway involves two separate steps: transduction and response
e. epinephrine is involved in response to stress