Biology Inheritance / Variation & Genetics ETEA 2023 Retake
PMDC Verified Question 40 of 94
Which of the following is true about occurrence of erythroblastosis foetalis?
A
Occurs when both father and mother are Rh +ve
B
Occurs when both father and mother are Rh -ve
C
Occurs when Mother is Rh +Ve and father is -ve
D
Occurs when mother is Rh -ve and father is Rh +ve
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Occurs when mother is Rh -ve and father is Rh +ve
Concept:

Erythroblastosis foetalis (Hemolytic Disease of the Newborn) is triggered by an Rh incompatibility between mother and fetus.

Solution:

  • The condition arises specifically when an Rh-negative mother conceives a child with an Rh-positive father.
  • If the fetus inherits the Rh-positive trait from the father, the mother's Rh-negative immune system will recognize the fetal Rh antigens as foreign.
  • The mother produces anti-Rh antibodies, which can cross the placenta in subsequent pregnancies and destroy the red blood cells of an Rh-positive fetus.


Why other options are incorrect:

  • If the mother is Rh-positive (Options A, C), her body already recognizes the Rh antigen as "self" and will not produce antibodies against an Rh-positive fetus.
  • If both are Rh-negative (Option B), the fetus will be Rh-negative, and no immune conflict will occur.

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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