To begin the process of photosynthesis, light energy must be converted to chemical energy through the use of the Light Reaction. The substances produced here are then, in turn, used in the dark reaction; which you will see later on.

              Photons, or little packages of light, are absorbed, or taken in by the pigments, chlorophyll a, chlorophyll b, and carotenoids. The light energy split the water molecule H2O to 2 hydrogen atoms and 1 oxygen atom, and is trapped by an acceptor a phosphate is added to the energy carrier, ADP (adenosine diphosphate), forming ATP (adenosine triphosphate)

              Light energy is initially converted to chemical energy in the form of 2 compounds: NADPH, a source of energized electrons (reducing power), and ATP, the versatile energy currency of cells. notice that the light reactions produce no sugar; that happens in the second stage of photosynthesis, the Calvin Cycle.
 

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