A researcher investigates a mutant cell line with a specific genetic defect: the alpha subunit of its stimulatory G protein can bind GTP upon receptor stimulation but lacks intrinsic GTPase activity. The cells are briefly exposed to a low concentration of epinephrine, which is then rapidly washed out of the extracellular medium. Based on this mechanism, what biochemical outcome will be observed in these mutant cells compared to normal cells?

A) Persistent elevation of intracellular cyclic AMP levels and sustained downstream phosphorylation even after epinephrine is removed

B) Complete inability of adenylyl cyclase to synthesize cyclic AMP despite receptor binding by epinephrine

C) Immediate prevention of receptor-ligand interaction due to permanent uncoupling of the G protein from the plasma membrane

D) Accelerated degradation of second messenger molecules caused by direct feedback inhibition of protein kinase A

Cell signaling Transitional Reasoning Download PDF

Biology · Cell Communication & the Cell Cycle · Biology · Cell Communication

1 Biology practice questions on Cell signaling. Questions that build towards applied reasoning.

Cell Communication & the Cell Cycle · Biology

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