Biology Bioenergetics SZABMU 2024
PMDC Verified Question 17 of 67
Which of the following does not take place during cyclic phosphorylation of the light dependent reaction of photosynthesis?
A
ATP synthesis
B
Light Absorption
C
Photoexcitation of electrons
D
Photolysis of water
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Photolysis of water
Concept:

Cyclic photophosphorylation is an alternate pathway that only involves Photosystem I to generate extra ATP.

Solution:

  • In cyclic flow, electrons are excited in PSI, travel down the cytochrome complex (generating ATP), and return directly back to PSI.
  • Because the electrons cycle in a closed loop, there is no electron deficit in PSI.
  • Therefore, there is no need to split water to replace electrons. Photolysis of water absolutely does NOT occur in this pathway.


Why other options are incorrect:

  • Light absorption, photoexcitation of electrons, and ATP synthesis are the fundamental driving events of the cyclic pathway.

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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