Light Reaction

"all about making ATP and storing hydrogen for the dark reaction"

Electron transport
	photosystem- chlorophylls and carotenoids grouped in clusters of a few hundred molecules in the thylakoid membrane
		types
			I
			  ancient
			II
			  newest
			  most energy efficient
	5 steps
		Step 1
			light absorbed by photosystem II
			chlorophyll's central magnesium atom loses energized electrons
		Step 2
			water is split
				Hydrogens' electrons replace those lost by chlorophyll
				Protons- left in stroma
				Oxygen- released as a byproduct
		Step 3
			Energized electrons move to ETC (electron transport chain)
			energy is used to pump protons inside the thylakoid
		Step 4
			Light absorbed by photosystem I
			chlorophyll's central magnesium atom loses energized electrons
			replaced by those from photosystem II
		Step 5
			Energized electrons enter another part of the ETC
			bond with NADP+ and a proton to form NADPH+
				(hydrogen fixation)
		CHEMIOSMOSIS
			occurs when there are protons on the inside & electrons outside
			protons pass through ATP synthase to make ATP
		ATP and NADPH+ are used in the dark reaction


ATP synthase converts potential energy from the concentration gradient of protons into chemical energy stored in ATP

Some protons in stroma are used to make NADPH+ from NADP+

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