In the ABO blood group system, red blood cells in humans have molecular differences between individuals. The differences are systematic and can be characterized according to a system of four different hereditary types; A, B, AB, and O. These types together form the blood group system, ABO. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay The differences in these four hereditary blood types are due to the four types having different variations or combinations of antigens. In the ABO group, antigens are carbohydrate chains in the membrane on the surface of red blood cells. Every human individual has antibodies against variants that he does not possess. Carbohydrate chains come in two main groups, A and B. Humans with type A blood have type A carbohydrate chains. Humans with type B blood have type B carbohydrate chains. Type AB humans have both types of chains, while type O humans have neither. In the plasma a human being always has antibodies against the A and/or B antigen that he does not possess. A blood type O person has both anti-A and anti-B, a blood type A person has anti-B, a blood type B person has anti-A, while a blood type AB person has no A or B antibodies. The genome that determines the blood group in the ABO system is located on chromosome 9 and there are three alleles A, B and O. The gene encodes an enzyme (glycosyl transferase) that attaches an additional unit of carbohydrates to H -antigen (oligosaccharide) on red blood cells. The B allele provides an enzyme that binds to galactose. The A allele provides an enzyme that binds to N-acetyl-galactosamine while the O allele provides a non-functional enzyme. In the ABO blood group system, red blood cells in humans have molecular differences between individuals. The differences are systematic and can be characterized according to a system of four different hereditary types; A, B, AB, and O. These types together form the blood grouping system, ABO. The differences in these four hereditary blood types are due to the four types having different variations or combinations of antigens. In the ABO group, antigens are carbohydrate chains in the membrane on the surface of red blood cells. Every human individual has antibodies against variants that he does not possess. Carbohydrate chains come in two main groups, A and B. Humans with type A blood have type A carbohydrate chains. Humans with type B blood have type B carbohydrate chains. Type AB humans have both types of chains, while type O humans have neither. In the plasma a human being always has antibodies against the A and/or B antigen that he does not possess. A blood type O person has both anti-A and anti-B, a blood type A person has anti-B, a blood type B person has anti-A, while a blood type AB person has no A or B antibodies. Please note: this is just a sample. Get a custom paper from our expert writers now. Get a Custom Essay The genome that determines blood type in the ABO system is located on chromosome 9 and there are three alleles A, B and O. The gene codes for an enzyme (glycosyl transferase) that attaches an additional carbohydrate unit to the H antigen (oligosaccharide) on red blood cells. The B allele provides an enzyme that binds to galactose. The A allele provides an enzyme that binds to N-acetyl-galactosamine while the O allele provides a non-functional enzyme.