Question

The most popularly known blood grouping is the ABO grouping. It is named ABO and not ABC, because 'O' in it refers to having

• A. No anitgens A and B on RBC's
• B. Other antigens besides A and B on RBCs
• C. Overdominance of this types on the genes for A and B types
• D. One antibody only either anti- A or anti- B on the RBCs

Answer 1

The correct option is A No anitgens A and B on RBC's

Antigens are foreign substances that induce the immune system to produce antibodies. The I${}^A$ and I${}^B$ alleles are responsible for the production of the A and B antigens that are present on the surface of the erythrocytes. The I${}^A$ and I${}^B$ alleles are dominant over $I^O$ allele. The antibodies are present in human blood without prior exposure to the antigen which means that people with a particular ABO antigen carry the antibody against the other antigen in their serum. A person with B blood group carries B antigen on their RBCs and anti- A antibodies in its serum. A person with A blood group carries A antigen on their RBCs and anti- B antibodies in its serum. Type O persons do not have either antigen on their RBCs and carry both antibodies in their serum.

Thus, the correct answer is option A.