Explain/Teach these Concepts to a Friend

1. Explain how Selig Hecht and his colleagues used random fluctuations in the number of absorbed photons to determine the minimal number of photons that are required to see a dim flash of light.
   
   
2. How does the mechanism of phototransduction in rod cells resemble hormone signaling through G-protein coupled receptors? For example, compare phototransduction to the mechanism of adrenalin (=epinephrine) action in the heart and liver.