Question

Blood group AB contains:
1. No antigen
2. No antibodies
3. No coagulant property
4. All of the above

Answer 1

Correct Answer - Option 2 : No antibodies

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.

Blood Group	A	B	AB	O
Antigens on RBCs	A	B	A and B	None
Antibodies in plasma	B	A	None	A and B
Can donate blood to	A and AB	B and AB	AB	A, B, and AB
Can receive blood from	A and O	B and O	A, B, O, and AB	O

• People with O blood group are termed as universal donors as they have neither antigens A nor B in their bloodstream which is why they can donate blood to any other blood type.