Biology Inheritance / Variation & Genetics NUMS 2022
PMDC Verified Question 57 of 94
Blood group which is known as universal donor is:
A
A-
B
O-
C
AB-
D
O+
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: O-
Concept:

Blood transfusions depend on ensuring the donor's red blood cells do not possess surface antigens that the recipient's immune system will attack.

Solution:

  • Blood group O negative (O-) is universally considered the universal donor.
  • It lacks both A and B antigens on the surface of its red blood cells, meaning it will not trigger anti-A or anti-B antibodies in a recipient.
  • Furthermore, being Rh-negative means it lacks the Rh antigen, ensuring compatibility with all recipient blood types regardless of their Rh factor.


Why other options are incorrect:

  • O+ has the Rh antigen and cannot be safely given to Rh-negative individuals.
  • A- and AB- possess surface antigens (A or both A & B) that will trigger immune rejection in individuals with opposing antibodies.

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.

Previous Question All Inheritance / Variation & Genetics MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App