Question

Where does the electron end up in the non-cyclic photophosphorylation?

• A. $NAD{P}^{+}$
• B. P700
• C. NADP reductase
• D. P680

Answer 1

The correct option is A

$NAD{P}^{+}$

The final destination of the electron is $NAD{P}^{+}$ where the additional electron is balanced by combining with $H^{+}$ released by the photolysis of water to form $NADP{H}_2$.

Electron released during photolysis of water is picked up by P680 of photocentre I. Electron extruded from here is passed through a series of electron carriers - pheophytin, plastoquinone, cytochrome b-f complex and plastocyanin. From plastocyanin, electrons are handed over to P700 of photosystem I. Electron extruded from here is passed through a series of electron carriers - special chlorophyll molecule X, Fe-S, ferredoxin, to finally reach $NAD{P}^{+}$. $NAD{P}^{+}$ then combines with $H^{+}$ with the help of NADP reductase to form NADPH.