Question

A person with blood group AB has which of the following antigens in his RBCs?
A. A
B. B
C. AB
D. none of these

Answer 1

Hint:- In 1900, Karl Landsteiner recognized four types of blood groups in human beings which is commonly called ABO blood grouping. The blood group in human beings is an example of multiple alleles and codominance effects.

Complete step-by-step solution:- The ABO blood groups are determined by the gene I having three alleles- IA, IB and i. In human beings, there are present two antigens A and B that are produced by IA and IB alleles respectively.
The surface of the red blood cells have these antigens. Two antibodies called anti A and anti B are also present in the plasma. Accordingly, the four blood groups are:
Blood group A that has antigen A and antibody B.
Blood group B that has antigen B and antibody A.
Blood group AB that has antigens A and B but no antibodies.
Blood group O that has no antigen but both the antibodies.
This is explained with the help of Landsteiner Law that states if an antigen is present on the red blood cells then antibody corresponding to it is absent in the plasma. Also, if the antigen is absent on the erythrocytes, the corresponding antibody is present in the plasma.
While doing blood transfusions, it is important to take care that the blood groups of the recipient and the donor match. If a transfusion is made between an incompatible donor and the recipient the reaction of antigens and antibodies will occur that will block blood circulation through capillaries.

Correct option: C. AB

Note:-
Human beings have another factor i.e. Rh factors in their blood. According to this, human blood can be categorized in two groups- Rh positive and Rh negative. At the time of blood transfusion, it is also taken into account.