In both photosynthesis and respiration, an electrochemical proton gradient drives chemiosmosis. what establishes the electrochemical gradient across a membrane to provide energy for atp production?

Hydrogen ions. Hydrogen ions are pumped across the membrane during electron transport. They are giving around the membrane by ability of energetic delivery. This establishes an electrochemical ability around the membrane like the single responsible for the action of nerve cells. Nerve cells use Potassium ions.  

When a high- and a low-pressure air mass are far apart, air moves quickly from high to low pressure.

Explanation: