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The first stage of the Light Dependent Reaction is when the photon (or particle of light, typically from the sun) hits the plant
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Once the photon hits the plant it causes an electron in the the chloroplast (specifically the Thykaloid) to jump to a higher energy level
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The energy that is created by the light hitting the electron and it jumping is captured as some of the electrons are forced to pass through the ETC (Electron Transport Chain), which is made up of proteins.
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The energy that is relesed as electrons move through the ETC is used to pump H+ into the thylakoid disc.
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The cells pump the H+ into the thylakoid disc to create an electrochemical gradient (ACTIVE TRANSPORT). It is active transport because it goes against it's concentration gradient AND it's charge (the cell is positively charged so H+'s don't want to go in), This forces the H+'s to flow through the ATP Synthase (PASSIVE TRANSPORT) which creates ATP!!! (that will be used later on to make glucose)
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As you probably remember, not all the electrons flow through the ETC. Some of them break away from their original chlorophyll molecule and are caught by NADP+. This requires 2 electrons!!! Which of course, makes this molecule negative, thus attracting H+'s that are in the chloroplast.
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Once the electrons and H+ bond with NADP you have... NADPH!! Which will be used later during THE CALVIN CYCLE!!!
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The chlorophyll is still upset because it has lost several electrons that it can't get back. So, the plant uses water (H2O) takes electrons from the H's (making it H+) releases the oxygen from the plant and keeps the H+ in the cell to release through the ATP Synthase
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Here's a video on photosynthesis... Enjoy!
https://www.youtube.com/watch?v=sQK3Yr4Sc_k -
The Light Dependent reaction was only one half of Photosynthesis! Now the plant must use the NADPH and ATP to make glucose (sugar or energy)
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Carbon-Dioxide is taken out of the air (1 molecule at a time) and is attatched to a carbon based molecule (organic molecule).
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ATP is added to the CO2 and organic molecule to give it energy, and NADPH adds electrons and hydrogens.
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The NADP+ is cycled back to the light reactions to get electrons that have jumped due to photons
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This happens for every CO2 individually as it enters the cell until 3 of them have gone through. This all happens twice until you have C6H1206 (glucose)
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6CO2+6H20--> C6H12O6+6O2
