Red blood cells (RBCs): Type A Positive (left) and type A Negative (right). The antigens and antibodies are large glycoproteins with unique molecular shapes. Each antigen has the complimentary antibody attached to it. The latter are "immune-type" (IgG) antibodies and readily pass through placental capillary membranes.Ī red blood cell (RBC) containing three different antigens on the surface of its membrane. Anti-Rh antibodies are smaller glycoproteins with a molecular weight of about 150,000. Anti-A and Anti-B antibodies are glycoproteins with a molecular weight of about 900,000. Each antibody has two combining sites where it attaches to the complimentary antigen on the surface of a red blood cell (RBC) membrane. Three different types of blood antibodies that circulate in the plasma. They have molecular weights of 200,000 to 300,000. The antigens are glycoproteins with unique molecular shapes. Models For Blood Agglutination By AntibodiesĪ red blood cell (RBC) with three different antigens on the surface of its membrane. If you include two variations of A (A 1 and A 2), there are a ten genotypes: A 1A 1, A 1A 2, A 2A 2, A 1O, A 2O, BB, BO, A 1B, A 2B and OO. Since the A, B and O alleles are located on one pair of loci on homologous chromosome pair number one, there are a total of six genotypes: AA, AO, BB, BO, AB, and OO.