Question

Assertion :Blood group 'O' have anti- A and anti- B antibodies. Reason: It does not have any antigens.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Both Assertion and Reason are incorrect.

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.

ABO blood groups are determined by the gene I (iosagglutinin). There are tree alleles, $I^A,I^B$ and $I^O$ of this gene. Proteins produced by the $I^A$ and $I^B$ alleles are called A antigen and B antigen. People with blood group A have the A antigen on the surface of their RBCs, and antibodies against antigen B in their plasma. Persons with blood group B have B antigen on their RBCs, and antibodies against A antigen in their plasma. Individuals with AB blood group have both antigen A and antigen B on their RBCs, and no antibodies for either of the antigens in their plasma. Type O individuals are without A and B antigens on their RBCs, but have antibodies for both these antigens in their plasma.