The A antigen (the protein that makes A blood A blood) is embedded in the red blood cell (RBC) membrane. Blood group A individuals will automatically carry antibodies (proteins that are in the blood plasma-liquid part of blood) that will attack blood group B cells. Blood group B individuals will carry antibodies that will attack blood group A cells. Blood group O individuals, lacking either of the A or B antigens will carry BOTH types of antibodies and will attack either A or B cells. When there is a transfusion with incompatible blood groups, cells can clump creating blockages in arteries throughout the body. Other pathways can lead to the lysing of RBCâs which will release their contents into the bloodstream elevating these component in the blood which can have sever effects on the heart (potassium primarily-in case you are interested).
Remember, the Rh is a typical one gene, two allele scenario. Rh+ blood can accept Rh+ or Rh- blood. A person with Rh- blood can only receive Rh- blood. Unlike ABO where an individual manufactures the antibody to an antigen they lack without prior exposure, the Rh factor requires previous exposure to illicit an immune response. If a Rh- person is exposed to Rh+ blood, the individual will create the antibody against the Rh antigen. Now, if Rh+ blood is introduced into this individual again, the recipientâs blood contains anti-Rh antibodies and will attack the Rh+ cells-Bad news for the recipient. This is the same thing that happens with an Rh- mom who gets pregnant with an Rh+ baby. By the time the first Rh+ baby is born and blood mixing may have occurred during late pregnancy (small breaks in the placenta can cause some of babyâs blood to mix with that of mom), first baby escapes unharmed. Subsequent babies arenât so lucky.
If there are small tears in the placenta (which are normal), momâs anti Rh antibodies can go in and attack the Rh+ babyâs blood. This can kill the baby. Now, Rh- moms are given a substance that will coat the babyâs RBCâ; kind of like putting them into stealth mode so they canât be seen by momâs immune system. Later-poof, out pops unaffected baby.
1. What blood type(s) can be given to an A positive individual?
2. If you have B negative blood, what blood types can you receive?
3. What blood types can an O negative receive? O positive?
4. If a man is blood group B and his wife is blood group A what blood type(s) are you 100% sure they could produce in their children?
5. If you have a blood group O father and a blood group B mother, can they produce an O child? Explain your answer.
6. You have a male friend who is blood group AB. He is successful in business but knows very little about biology. His wife just had an O child. Knowing that you have been studying the genetics of blood groups, he asks you for an education on blood groups. What do you think about this situation?
7. A woman is AB and her husband is A. They have a B child. What are all the blood groups possible in their children if he is heterozygous?
8. A woman is Rh- and her husband is Rh+. Their first baby is Rh-. What is the genotype, with respect to Rh, of the parents? What is the probability their next child will be Rh+? Does the woman have to worry about any issues with future children? Explain!
