Biology Biotechnology PMDC Conceptual Practice
PMDC Verified Question 31 of 65
SCID patients lack which enzyme essential for lymphocyte maturation?
A
Homogentisic oxidase
B
Phenylalanine hydroxylase
C
Beta-galactosidase
D
Adenosine deaminase
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Adenosine deaminase
Concept:

Inborn metabolic defects in severe combined immunodeficiency.

Solution:

Adenosine Deaminase (ADA) deficiency causes toxic purine metabolic accumulation (deoxyATP), destroying T and B lymphocytes and resulting in Severe Combined Immunodeficiency (SCID).

Why other options are incorrect:

  • Homogentisic oxidase: Deficiency leads to alkaptonuria (black urine disease).


  • Phenylalanine hydroxylase: Deficiency causes phenylketonuria (PKU).


  • Beta-galactosidase: Lysosomal enzyme deficiency causes \( \text{G}_{M1} \) gangliosidosis.

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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