Biology Bioenergetics UHS 2022
PMDC Verified Question 51 of 67
Each carrier in electron transport chain is first and then .
A
Broken-down, regenerate
B
Generated, broken down
C
Oxidized, reduced
D
Reduced, 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: Reduced, oxidized
Concept:

The electron transport chain (ETC) is a series of consecutive redox (reduction-oxidation) reactions.

Solution:

  • When an electron carrier accepts an electron from the previous molecule, it gains a negative charge and becomes reduced.
  • When it passes that electron to the next carrier in the chain, it loses the electron and becomes oxidized again.
  • Thus, the sequence is always reduced, then oxidized.


Why other options are incorrect:

  • Starting with oxidized would mean it loses an electron before gaining one, which contradicts the chain flow. Carriers must first receive (reduce) before they can give (oxidize).

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.

Previous Question All Bioenergetics MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App