A mutation in the active site of adenylyl cyclase that inactivates it would most likely lead to __________.

What role do phosphatases play in signal transduction pathways?

a) They phosphorylate proteins involved in signal transduction or cellular response.

b) They activate protein kinases by phosphorylation.

c) They amplify the signal molecule.

d) They regulate the function of proteins involved in signal transduction pathways or cellular response.

Phosphorylation cascades are useful signal transduction pathways because they ________.

a) Allow proteins to be easily activated by adding or removing a phosphate group.

b) Allow proteins to be easily deactivated by adding or removing a phosphate group.

c) Amplify the original signal many times.

d) All of the above.