Sun light in the form of photons (packets of energy) excites electrons within the chloroplast. The electron jumps and eventually stimulates the membrane to open up. Once it's open hydrogens flow in and as that's happening, enzymes help break the bond in H2O (water). Then O2 flows out of the thylakoid and the hydrogens are kicked out as well through ATP synthase this stimulates another reaction in which ADP and P+ join to make ATP (adenosine tri phosphate). On the other side of the membrane the same electron that was excited stimulates another reaction in which NADP and H+ joint to make NADPH.

Once this occurs NADPH and ATP are picked up by the stroma and through the benson cycle they help creat C6H12O6 (glucose).

So to recap CO2 + H2O form C6H12O6 + O2

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