Biology Homeostasis PMDC Conceptual Practice
PMDC Verified Question 2 of 99
The catabolic deamination of amino acids in the human liver initially generates which toxic nitrogenous compound?
A
Ammonia
B
Arginine
C
Ornithine
D
Urea
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Ammonia
Concept: Hepatic amino acid catabolism.

Solution: Deamination involves the enzymatic removal of the amino group (\(\text{-NH}_2\)) from an amino acid. This group immediately accepts a hydrogen ion to produce highly toxic ammonia (\(\text{NH}_3\)), which is subsequently converted into urea via the urea cycle.

Why other options are incorrect:
  • Option B & Option C (Arginine & Ornithine): Intermediate amino acids formed during the hepatic urea cycle.

  • Option D (Urea): The end-product synthesized from ammonia and carbon dioxide in the liver.

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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