Biology Bioenergetics NUMS 2023
PMDC Verified Question 33 of 67
When light falls on P700, which event is likely to occur?
A
It induces photolysis
B
Gains hydrogen
C
Accept electrons
D
It is oxidized
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: It is oxidized
Concept:

P700 is the specialized pair of chlorophyll a molecules at the reaction center of Photosystem I.

Solution:

  • When P700 absorbs photon energy (either directly or via antenna pigments), its electrons become highly excited.
  • These excited electrons are physically ejected out of the molecule and transferred to a primary electron acceptor.
  • Losing electrons chemically means that P700 becomes oxidized.


Why other options are incorrect:

  • Photolysis (splitting of water) is induced by P680 (Photosystem II), not P700.
  • It loses electrons rather than accepting them initially (it accepts them later from the ETC to regenerate).

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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