The energy source for ATP Synthesis ...

[Havoc]

Ok the question being asked is: "The energy source for ATP Synthesis following energy released in the Electron Transport Chain in both photosynthesis is?"
Is it H2O?
If so then what are the principle reactants of photosynthesis?

[b_d_41501]

6H2O + 6CO2 ----------> C6H12O6+ 6O2

So water and CO2 are the principle reactants. I guess you could say H20 is the answer since it is converted into H+ ions and 02- ions which go on to do their respective duties.

[mith]

Well the energy source is the sun which allows the photolysis. Water is the electron source. ATP synthesis happens due to the proton gradient.

[MrMistery]

Mithril is right. In photosynthesis the energy source are the photons absorbed by chlorophil a. H2O only gives you electrons and protons, and CO2 gives you carbon and oxigen. ATP is synthesised due to the proton gradient. This gradient results from decomposing the water molecule, but this requires an external source of energy, which is light. Therefore, the light is the source of energy, not water
Regards,
Andrew