A donor having blood group AB cannot donate his/her blood to the recipient who has blood group O because

A donor having blood group AB cannot donate his/her blood to the recipient who has blood group O because Correct Answer donor has both the antigens

Concept:

• The human blood group (ABO blood group) shows multiple allelism where one character is governed by three alleles
• The ABO blood group gene I (Iso agglutinogen) is present on the 9th chromosome. Gene I has three alleles IA, IB, IO 
• IA allele forms a sugar on the plasma membrane of RBC called a-antigen.
• IB allele forms a different sugar on the RBC called b-antigen.
• IO does not form any antigen.
• Alleles IA and IB are dominant over allele IO but co-dominant to each other.
• The ABO blood grouping is used to determine the blood group of an individual based on the presence or absence of antigens A & B.

Explanation:

• People with blood group AB have both antigen A & B present in their bloodstream, they do not have any antibodies present
• Due to the absence of antibodies in the blood, they are called universal recipients as they can receive blood from any other type.
• People with blood group O do not have any antigens present but, they have both the antibodies A & B present in their bloodstream.
• Due to the absence of antigens in the blood, they are called universal donors as they can donate blood to any other type.
• A donor having blood group AB  cannot donate their blood to the recipient who has blood group O, this is because the antigens present in the blood of the donor (AB) would react with the antibodies of the recipient's (O) blood and this will cause destruction of the recipient's RBCs and the person may die.

Important Points