A protein kinase cascade can amplify an intracellular signal by
A) opening gap junctions to allow diffusion of signals from neighboring cells.
B) activating a G protein, which then binds and activates a second protein, amplifying the signal.
C) using nitric oxide to quickly diffuse into cells, amplifying the response.
D) using transcription factors to increase gene expression.
E) activating one kinase molecule that can then trigger the activation of many proteins.

Question

Quizplus · Accepted Answer

A protein kinase cascade involves a series of kinases activating each other through phosphorylation. This amplifies the original signal because one activated kinase molecule can activate multiple downstream proteins, leading to a larger overall response. This process does not involve gap junctions, G proteins, nitric oxide, or transcription factors.

A Protein Kinase Cascade Can Amplify an Intracellular Signal by