Photosynthetic electron transport establishes a transmembrane gradient of proton concentration, a proton motive force, that serves to drive the ATPase reaction in the direction of ATP synthesis.
Photosynthesis occurs inside chloroplasts. Chloroplasts contain chlorophyll, a green pigment found inside the thylakoid membranes. These chlorophyll molecules are arranged in groups called photosystems. There are two types of photosystems, Photosystem II and Photosystem I. When a chlorophyll molecule absorbs light, the energy from this light raises an electron within the chlorophyll molecule to a higher energy state. The chlorophyll molecule is then said to be photoactivated. Excited electron anywhere within the photosystem are then passed on from one chlorophyll molecule to the next until they reach a special chlorophyll molecule at the reaction centre of the photosystem. This special chlorophyll molecule then passes on the excited electron to a chain of electron carriers.
Animation created by Wes Bellanca and Memorie Yasuda. Earthguide
These organisms―the plants in particular―resort to photosynthesis to convert carbon dioxide into organic compounds by using the energy derived from the Sun.
IB Biology Notes - 8.2 Photosynthesis
'Linear electron transport' involves electrons (e-) being derived from the splitting of water, by PSII, and sequentially passed along the photosynthetic e- transport chain by plastoquinone (PQ), cytochrome bf (Cytbf), plastocyanin (PC), Photosystem I (PSI) and PSI-bound ferredoxin (Fd), before being used for producting NADPH by ferredoxin–NADP+ oxido-reductase (not shown) in the Stromal matrix (Stroma).
Photosynthesis Interactive (HTML5) - Bioman Bio
For oxidative phosphorylation the electrons come from hydrocarbon and carbohydrate structures, whereas in photosynthesis, the electrons have to be energized in the magnesium center of chlorophylls.