Biology · Bioenergetics
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How does each photoexcited electron pass from PS2 to PS1?
- A
ETC
- B
Chemiosmosis
- C
Photolysis
- D
Photosynthesis
Light excites electrons in chlorophyll P680 in PSII.
These high-energy electrons are transferred to the primary electron acceptor of PSII.
The electrons pass through a series of electron carriers in the ETC, including:
Plastoquinone (PQ)
Cytochrome b6f complex (which pumps protons into the thylakoid lumen, aiding ATP synthesis)
Plastocyanin (PC) (which transfers electrons to PSI)
Excitation in Photosystem I (PSI)
The electrons arrive at chlorophyll P700 in PSI, where they get re-excited by light.
The energized electrons are then passed to ferredoxin (Fd) and finally used to reduce NADP+ to NADPH.
The correct answer is: ETC (Electron Transport Chain)
Excitation in Photosystem II (PSII)
Light excites electrons in chlorophyll P680 in PSII.
These high-energy electrons are transferred to the primary electron acceptor of PSII.
The electrons pass through a series of electron carriers in the ETC, including:
Plastoquinone (PQ)
Cytochrome b6f complex (which pumps protons into the thylakoid lumen, aiding ATP synthesis)
Plastocyanin (PC) (which transfers electrons to PSI)
Excitation in Photosystem I (PSI)
The electrons arrive at chlorophyll P700 in PSI, where they get re-excited by light.
The energized electrons are then passed to ferredoxin (Fd) and finally used to reduce NADP+ to NADPH.
Chemiosmosis → This refers to ATP synthesis using a proton gradient but does not directly transport electrons.
Photolysis → This is the splitting of water in PSII to release electrons, but it does not describe electron transfer.
Photosynthesis → This is the overall process that includes the ETC but is too broad an answer for this specific question.
Tagged under Biology · Bioenergetics · 2021