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NS FL # 6, Q53 biology

Posted: Sat May 25, 2019 2:03 pm
by sdaswani
Hi! Could you please help explain why A is a better answer choice than C? Thanks!!

Re: NS FL # 6, Q53 biology

Posted: Sun May 26, 2019 8:48 am
by NS_Tutor_Will
Thanks for the question!

Since adenylyl cyclase activity would be stopped after the G protein signal stopped being sent, if it were to continue that implies that the signal isn't being stopped. Since the signal isn't being stopped, it follows that the means by which that signal is stopped have been disrupted. In other words, the GTPase (cleaving) subunit isn't working. C doesn't make sense because adenylyl cyclase isn't just activated willy-nilly whether or not the signal is present. It requires the GPCR-ligand to kick off its activity, and it wouldn't start on its own in the absence of that signaling.

I hope this helps!