Biology Biomolecules SZABMU 2022
PMDC Verified Question 81 of 142
Which bond is the potential source of chemical energy for cellular activities?
A
C-R
B
C-N
C
C=O
D
C-H
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: C-H
Concept:

Cellular respiration extracts thermodynamic energy stored in highly reduced organic molecules.

Solution:

  • The electrons shared within the non-polar Carbon-Hydrogen (C-H) bonds are held relatively loosely compared to polar bonds (like C=O).


  • Because they are held loosely, these electrons possess high potential energy.


  • During cellular respiration, these high-energy electrons are stripped from the C-H bonds and allowed to 'fall' towards highly electronegative oxygen, releasing massive amounts of usable chemical energy to synthesize ATP.


Why other options are incorrect:

  • C=O: Highly oxidized bonds holding electrons tightly in a low-energy state.


  • C-N / C-R: Not the primary thermodynamic fuel utilized during massive oxidative phosphorylation.

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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