Chemiosmosis.
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   As  electrons  pass  along the ETC, protons are pumped from the stroma
   into the thylakoid space, forming a H^+ gradient.
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   The protons diffuse back to the stroma by chemiosmosis, and powers the
   ATP synthase to make ATP.
<P>
   These  light  reactions  store chemical energy in NADPH and ATP, which
   are used in the Calvin cycle.
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   Exercise:  <A Href="http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/activities/load.html?10&D" oNClick="popact('http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/activities/load.html?10&D');return false;"><iMg sRc="/images/tutorial.gif" aLt='' boRDer=0></A>