Electrons generally move from a more negative (lower) or less positive redox potential to less negative or a more positive (higher) redox potential, reflecting a downhill energy flow. However, in the Z-scheme of photosynthesis, there are two key points where light energy is used to excite electrons, allowing them to move uphill to a more positive redox potential.

Electrons generally move from a more negative (lower) or less positive redox potential to less negative or a more positive (higher) redox potential, reflecting a downhill energy flow. However, in the Z-scheme of photosynthesis, there are two key points where light energy is used to excite electrons, allowing them to move uphill to a more positive redox potential.

NCERT LINE BY LINE, Photosynthesis, pre-class /

Electron Carrier Redox Potential (mV) Water (H₂O) +820 mV P680 (PSII reaction center) +1,200 mV Pheophytin (Pheo) -500 mV Plastoquinone (PQ) +80 mV Cytochrome b6f complex +300 mV Plastocyanin (PC) +370 mV P700 (PSI reaction center) +600 mV A₀ (first acceptor in PSI) -1,100 mV A₁ (Phylloquinone) -800 mV Iron-sulfur clusters (FX, FA, FB) -705 […]

Electrons generally move from a more negative (lower) or less positive redox potential to less negative or a more positive (higher) redox potential, reflecting a downhill energy flow. However, in the Z-scheme of photosynthesis, there are two key points where light energy is used to excite electrons, allowing them to move uphill to a more positive redox potential. Read More »