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MDCAT
Biology
2007

Biology · Variation and Genetics

Work through this past-paper style MCQ, then read the full explanation. Practice more biology questions on mMCQ with adaptive practice and topic analytics.

Question

O Group is universal donor because:

Options
  • A

    It has both A & B Antigens

  • B

    No Antigens

  • C

    A antigen

  • D

    B Antigen

Explanation

Blood group O is considered the universal donor because it has no A or B antigens on the surface of its red blood cells, which means it does not trigger an immune response when transfused into a person with any other blood type. In contrast, if blood type O had A, B, or both antigens, it could cause an immune reaction in recipients with different blood types, as their immune systems would recognize the antigens as foreign. Therefore, options stating the presence of A or B antigens are incorrect.

This is incorrect. If blood type O had both A and B antigens, it could trigger an immune response in recipients with different blood types.

This is correct. Blood type O is a universal donor because it lacks A and B antigens, preventing an immune response in recipients.

This is incorrect. Blood type O does not have A antigens, which is why it can be donated to any blood group without causing an immune reaction.

This is incorrect. Blood type O does not have B antigens, allowing it to be safely transfused to recipients of any blood type.

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Tagged under Biology · Variation and Genetics · 2007