AP BIOLOGY

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THE CELL

CELL COMMUNICATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A mutation in the active site of adenylyl cyclase that inactivates it would most likely lead to ____
A
an increase in the amount of cAMP present in the cell
B
higher activity of protein kinase A
C
reduced binding of adenylyl cyclase to protein kinase A
D
lower activity of protein kinase A
E
increased binding of adenylyl cyclase to the G protein that activates it
Explanation: 

Detailed explanation-1: -Guanine nucleotide-binding protein G(i) alpha (Gi-alpha) inhibits adenylate cyclase, thus inhibiting the production of cAMP from ATP and ultimately decreasing the activity of cAMP-dependent protein kinase.

Detailed explanation-2: -Adenylyl cyclase is a membrane-bound enzyme that catalyzes the conversion of ATP to cAMP. [1] cAMP, an intracellular second messenger, activates protein kinase A by dissociating its regulatory subunit from the catalytic subunit.

Detailed explanation-3: -What would need to occur in the cell to deactivate the protein kinase enzymes? The phosphate groups would need to be removed.

Detailed explanation-4: -The enzyme adenyl cyclase, itself activated by the hormone adrenaline (epinephrine), which is released when a mammal requires energy, catalyzes a reaction that results in the formation of the compound cyclic adenosine monophosphate (cyclic AMP).

There is 1 question to complete.
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