Body Fluids and Circulation — BIOLOGY STD 11 Science — Question

ABO blood groups in human beings were reported for first time by Karl Landsteiner. ABO blood groups are determined by the gene/ (isoagglutinin). There are three alleles, IA, IB and 7° of this gene. Proteins produced by the/ A and/ ll alleles are called A antigen and B antigen respectively. People with blood group A have the A antigen on the surface of their RBCs, and antibodies to 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. Individuals with blood group AB can receive blood of A, B or O group, while those with blood group O can donate blood to anyone. This is the most important blood group for transfusion. Thus person with blood group AB is called universal recipient and person with blood group O is called universal donor. If a blood transfusion is made between an incompatible donor and recipient, reaction of antigens on the cells and antibodies in the plasma produces clots and clog capillaries,
Table: Human ABO blood groups and their compatibility.

Blood Group	Genotype	Antigens on red blood corpuscles	Antibodies in blood plasma	Can give blood to	Can get blood from
A	|A|A Or |A|O	A	b	A, AB	A, O
B	|B|B Or |B|O	B	a	B, A	B, O
AB	|A|B	AB	None	AB	AB, A, B, O
O	|O|O	None	a, b	AB, A, B, O	O