Transcript File
Understanding Blood & Blood Type Experiments with blood transfusions, have been carried out for hundreds of years. Mixing blood from two individuals can lead to blood clumping. The clumped red cells can crack and cause toxic reactions. This can have fatal consequences. In 1901, Karl Landsteiner discovered that blood clumping occurred when the receiver of a blood transfusion had antibodies against the donor. His work made it possible to determine blood types and thus paved the way for safe blood transfusions. What are antigens & antibodies? The differences in human blood are due to the presence or absence of certain protein molecules called antigens and antibodies. The antigens are proteins located on the surface of the red blood cells’ plasma membrane. The antibodies are proteins in the blood plasma. What are the different blood groups? Individuals have different types and combinations of these molecules. The blood group you belong to depends on what you have inherited from your parents. What happens when different blood types are mixed? Not all blood groups are compatible with each other. Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals. This occurs because the antibodies of the recipients’ blood attach to the antigens of the donor blood. The red blood cells are linked together, like bunches of grapes, by the antibodies. What is the Rh Factor? Many people also have the Rh factor. This is also an antigen found the surface of the red blood cell. Those who have the antigen are called Rh+. Those who don't, are called Rh-. A person with Rh- blood can develop Rh antibodies in the blood plasma if Rh+ blood is received. The Rh antigens can trigger the production of Rh antibodies. A person with Rh+ blood can receive blood from a person with Rh- blood without any problems. How is blood type genetically determined? Blood type is determined by the ABO & Rh genes. The ABO genes are determined by multiple and co-dominant alleles. Remember that an allele is one of several different forms of a gene. There are three different alleles for human blood type: IA ,IB , & i Since there are 3 different alleles, there are 6 different possible genotypes and 4 different possible phenotypes. Phenotype/ Blood Type Genotype Meaning ii Neither A nor B antigens are present O A IAi B IB i AB or IA IA Only the A antigen is present or IB IB Only the B antigen is present IAIB A & B antigens are present Blood Transfusions - who can receive blood from whom? The transfusion will work if a person who is going to receive blood has a blood group that does NOT have any antibodies against the donor blood's antigens. But if a person who is going to receive blood has antibodies matching the donor blood's antigens, the red blood cells in the donated blood will clump. Play Blood Typing Game Blood Types Antigens Antibodies Can give blood to Can receive blood from AB A&B none AB AB, A, B, O A A B A & AB A&O B B A B & AB B&O O none A&B AB, A, B, O O •The Universal Donor can donate blood to any blood type. •Which blood type is the Universal Donor? •The Universal Recipient can receive blood from any blood type. •Which blood type is the Universal Recipient? Practice Problems! Give the possible genotypes & phenotypes of the following crosses. 1. IAIA x IBi Genotypes: IAIB IAi Phenotypes: AB, A 2. IBi x IAi Genotypes: IAIB IBi IAi ii Phenotypes: AB, B, A, O 3. Type O x Type AB Genotypes: IAi IBi Phenotypes: A, B Who’s Baby is it? At the hospital, 2 newborn babies were accidentally mixed up and the parents questioned which baby belonged to whom. The blood groups of everyone involved is listed below. Determine which baby belongs to which couple. Baby 1 – Type A Baby 2 – Type O Mr. Brown – Type AB Mrs. Brown – Type B Mr. Smith – Type B Mrs. Smith – Type B Who’s baby is it? answer… Baby 1 has to belong to Mr. & Mrs. Brown. There is no way that they could create a Type O (ii) baby when only one parent could possibly contain the I allele. Baby 2 has to belong to Mr. & Mrs. Smith. There is no way that they could create a Type A (IA IA, IAi) baby with out either carrying the IA allele. Which child is adopted? The Tyler family has three kids, one of which is adopted. The blood types of the parents and children are listed below. Determine which child is adopted. Mom-Type AB JohnType B Dad- Type O Martha- Type AB Zackary- Type A Which child is adopted? ANSWER Martha (IAIB) is adopted because Dad is Type O (ii) and could not have given either of her two alleles. Dr. Charles Drew Today's American Red Cross blood program is the result of the efforts of Dr. Charles R. Drew, an African-American blood specialist, surgeon, educator and scientist. His pioneering work in blood collection, plasma processing and transfusion laid the foundation for modern blood banking. Timeline Did you Know? That Drew attended Amherst College in Massachusetts, then medical school at Montreal's McGill University in Canada. At Amherst College, Drew received an athletic scholarship and was made captain of the school’s track team and winner of the football team's most valuable player award. That he made many of his discoveries on blood while doing graduate research at Columbia University in New York City. That Drew became the first African American to receive a Doctor of Medical Science degree from Columbia University. That he returned to his hometown of Washington, D.C., from the Red Cross blood project in New York and continued to teach the next generation of African American doctors as a professor of surgery at Howard University.