Question

In the following table of human ABO groups, fill up the blanks (i), (ii), (iii) and (iv) from the options given below.

Blood group	Antigens on RBCs	Antibody in plasma	Donor groups
A	A	Anti-B	A,O
B	B	Anti-A	B,O
AB	AB	(ii)	A,B,AB,O
O	(i)	(iii)	(iv)

(A) i – Nil, ii – Nil, iii – Anti-A, B, iv – AB
(B) i – Nil, ii – Nil, iii – Nil, iv – O
(C) i – Nil, ii – Anti-A ,B, iii – Nil, iv – O
(D) i – Nil, ii – Nil, iii – Anti-A, B, iv – O

Answer 1

Hint:-The ABO group in humans is a classification of the human blood group based on the antigens present on the red blood cells (RBC). The antigens present may be of glycolipids, proteins, carbohydrates or glycoproteins depending on the blood group.

Complete Answer:-

Karl Landsteiner discovered ABO blood groups in 1900. The mechanism involved in grouping is based on the antigens on RBCs and antibodies in the serum. All ABO blood groups have O-linked glycoproteins to which certain sugar residues that may or may not be attached. The sugar residue exposed helps in determining the blood group. As given in the table, blood group A has an antigen on RBC and anti-B antibody in plasma. Similarly, blood group B has the B antigens and anti-A antibody in plasma. However, blood groups AB and O are quite different.
AB group has both the antigens A and B on RBC but neither of their antibodies in the plasma.
Contrastingly, blood group O has neither of the neither A nor B antigens but has both anti-A and anti-B antibodies in their plasma.
The identification and grouping of different blood groups has its importance during blood transfusion and pregnancies. The antibodies in the plasma belong to the IgM antibody family. Hence, any mismatch in the blood group during transfusion of blood to the recipient will result in fatal immune reactions. Individuals with O blood group have both anti-A and anti-B antibodies. Therefore, they can donate blood to only individuals with O blood groups.
Thus, the correct answer is (D) i – Nil, ii – Nil, iii – Anti-A, B, iv – O.


Note:- Blood group O-negative is often called ‘universal donor’ as they do not have antigens. Similarly, AB-positive is called ‘universal recipient’ as they can receive red blood cells of any blood type.
Similarly, plasma can be donated and received. It is an inverse of RBC compatibility.