Final answer:
The special pair of chlorophyll a molecules in photosystem I does not serve as the final electron acceptor in the photosynthetic electron-transport chain.
Step-by-step explanation:
The chlorophyll special pair in photosystem I does not serve as the final electron acceptor in the photosynthetic electron-transport chain.
Instead, the final electron acceptor in photosystem I is an electron acceptor protein called ferredoxin. After the special pair of chlorophyll a molecules in photosystem I become excited, they transfer electrons to ferredoxin, which then passes the electrons to the electron transport chain.
This chain consists of several protein complexes that ultimately transfer the electrons to the final electron acceptor, NADP+, which is reduced to NADPH.