Could someone please explain this AP Biology question? I know the answer is C but I do not understand why. Doesn't Smo prevent gene transcription? If you "block its activity" then wouldn't it cause gene transcription, whereas the goal of treating cancer is to prevent transcription? Please help!
I'm just going to outline the alternatives, I'll leave validating why choice C to you.
Choice A. If the new molecule acts in the same fashion as Hh, the results will be identical. If the new molecule bound to Pct but did not effect a response, that might work.
Choice D. Addition of Ci into the nucleus initiates transcription which seems to be the issue here.
Choice B. Best wrong answer! Can you inject enough stem cells to make a difference? Will the cells have some adverse effect? More importantly, the binding of messengers to receptors is a reversible process. The Hh will be able to detach from Ptc on the stem cells and eventually interact with Ptc on the native cells.
So, what effect will Hh have if the Smo in unable to respond?