Two waters enter Photosynthesis

Water -

H2O
H2O
--------------
2 H2 >>> O2    Our Oxygen comes from 2 water molecules

CO2
C O    O
H2   H2
----------------
CH2O + H OH Sugar

THE LIGHT SIDE: Oxygen is removed from water !!

Chlorophyll absorbs sunlight and photons then knock loose electrons out of water.
The electrons then go to NADP molecules. . . easy ?
More electrons from water are supplied.
Some ATP , fuel, is made as electrons and protons flow and then enters the Dark Side
along with 2 NADPH. Carbon enters leaf on Dark Side and Calvin Cycle.

NADP + 2 e- + H+ = NADPH

NADPH , NADPH , ( 2 H+ )
The electrons are in two NADPH

IN THE DARK SIDE: Hydrogen is added to carbon !!

NADPH ....Carries 2 electrons and a proton into the dark side to meet Carbon.

Now in the dark side we have 4 hydrogens from 2 water molecules,
remember 2 H2 + >>> O2 . Oxygen has now gone for us to breathe !
A H2 goes into the incoming CO2 to make CH2O + O.
The second oxygen and other hydrogens don't really make H2O
and we get CH2O = Sugar and a spare H OH not a water molecule.

They say " water splits ". Water + Light . >> . 2H+ + 2e- + O
. . . . . . . . . . 2 H2 + >>> O2
. . . . .CO2 + 2 H2
. . . . CH2O2 + H2
. . . . . CH2O + H OH = Sugar and water

From light-side to dark-side and Calvin Cycle ;
6-times this is needed for one sugar molecule.
2 NADPH + 3 ATP + 2H+

energized electrons get transferred to Calvin Cycle
NADPH is NADP+ + 2 e- + H+ or . . . NADP + H + e-.

This molecule is reused and travels back and forth
carrying electrons and a proton to link to carbon.

Chloroplast
Thykaloid / grana / chlorophyll = light side
Stroma calvin cycle = dark side
ADP + Pi >>> ATP + H2O

Water
O2 <<<< 2 H2 + CO2 = CH2O - H2O

Sugar back to water
CH2O - H OH - O2 = CO2 - 2 H2O

----------

2 H2O >>>> O2
   H2 + H2
H CO2
CO + O
   H2 + H2
-----------------
CH2O - H OH

1 sugar = 36 ATP

A simple balanced equasion for Photosynthesis
    H2O . >> . . . . H2

    H2O . >> . . . . H2   + CO2
---------- . . . ------------------
. . O2 . . . . . . . CH2O
. . . . . . . . . . . . H OH

My Calvin . . . equasion

Photosynthesis

My Photosynthesis . . . equasion

Carbon -fixation cycle . . . wait for graphics

Calvin Cycle

Respiration . . . the reverse process

Lots of answers

My own image for the 1st time on my web site. April '05
Example of me working on an equasion

into the Calvin Cycle.

Sept. '08
This Wikipedia says the early Oxygen fused to iron in the ocean.