Biology Bioenergetics SZABMU 2024
PMDC Verified Question 16 of 67
The step of Calvin Cycle during which five molecules of Glyceraldehyde 3-phosphate (G3P) are converted in Ribulose 1,5-Phosphate by utilizing 3 molecules of ATP is:
A
Fixation
B
Reduction
C
Regeneration
D
Phosphorylation
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Regeneration
Concept:

For a biochemical cycle to continuously run, its starting material must be remade at the end of every turn.

Solution:

  • The starting molecule of the Calvin cycle is RuBP.
  • After the reduction phase, some G3P exits the cycle, but the majority (5 out of 6 molecules) remain.
  • Through a complex series of ATP-dependent reactions, these five 3-carbon G3P molecules are rearranged to regenerate three 5-carbon RuBP molecules.
  • This specific final phase is fundamentally called the Regeneration step.


Why other options are incorrect:

  • Fixation is the attachment of \( CO_2 \).
  • Reduction uses ATP and NADPH to convert 3-PGA to G3P.

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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