Biology Homeostasis PMDC Conceptual Practice
PMDC Verified Question 45 of 99
The hepatic urea cycle functions primarily to convert which highly toxic nitrogenous product into a less harmful form?
A
Creatine
B
Carbon dioxide
C
Amino acids
D
Ammonia
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Ammonia
Concept: Detoxification of ammonia in the liver.

Solution: Free ammonia is highly neurotoxic. The liver utilizes the metabolic urea cycle to combine two molecules of ammonia with carbon dioxide to synthesize non-toxic, water-soluble urea.

Why other options are incorrect:
  • Option A & Option C: Creatine and intact amino acids are metabolic metabolites, not toxic waste molecules requiring conversion to urea.

  • Option B (Carbon dioxide): \(\text{CO}_2\) is utilized as a substrate in the urea cycle, but the primary toxic entity being detoxified is ammonia.

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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