What is the structure and function of "electron transport chain" in chloroplast and mitochondria?

1 Answer
Feb 15, 2018

The structure is a series of proteins embedded in a membrane that pump hydrogen ions in one direction to create a concentration gradient - the function is generate ATP.


The electron transport proteins accept high energy electrons from the electron carriers NADPH (in photosynthesis) and NADH & FADH2 (in cellular respiration), and through the action of transporting them from one to the other in a series of electron exchanges, small units of energy are extracted and used to pump hydrogen ions.

I cell respiration they are pumped from the matrix into the intermembrane space of the mitochondria - in photosynthesis they are pumped from the stroma into the lumen of the thylakoids.
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In both cases, the high concentration of hydrogen ions can't cross the membrane (due to their charge), and place a great deal of osmotic pressure on the membrane. This pressure drives the hydrogen ions from [high] --> [low] through the enzyme ATP Synthase - using this energy to produce ATP molecules.