= Light-dependent reactions
{wiki}
In a <chloroplast>, <light-dependent reactions> take place at <thylakoid> membranes. <Chlorophyll> captures <light>; <Electron> transfer helps establish an <electrochemical gradient> across the <thylakoid> membrane, enabling formation of <ATP>. The <oxygenic photosynthesis> pathway also forms <NADPH> and releases <molecular oxygen> from <water>. <ATP> and <NADPH> become available in the <chloroplast stroma> for the <Calvin cycle>. See https://www.ncbi.nlm.nih.gov/books/NBK26819/[Alberts et al.: chloroplast light reactions].
\Image[/chloroplast-photosynthesis-compartments.png]
{title=<Thylakoid> membranes and <chloroplast stroma> couple two stages of <photosynthesis>}
{description=Original <chloroplast> schematic, not an experimental photograph or a scale drawing. <Light-dependent reactions> supply <ATP> and <NADPH> to the stromal <Calvin cycle>; depleted carriers return for reuse. The <molecular oxygen> arrow leaves the <water>-using stage, while <carbon dioxide> enters <carbon fixation>.}
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