Blood type is an example of a single gene that has multiple alleles in humans. One gene codes for proteins on the surface of red blood cells. Each of the three alleles (A, B, or O) is a code for a different protein on the surface of the red blood cells. The
B allele produces b type proteins, the A allele produces a type a type proteins, and the O allele does not produce any proteins.
Your immune system recognizes the proteins on your red blood cells and identifies them as belonging to you. If cells with a different protein enter your body, your immune system will attack them. Alleles A and B are co-dominant. The O allele is recessive. As a result, the following blood types in humans are possible:
Genotypes Surface Protein Phenotypes
AA or AO
BB or BO
AB
OO
A
B
A and B
None
A
B
AB
O
1. Max has been told that because his blood has no surface proteins he can give blood to anyone.
Therefore he has Type ____ blood and is called a universal _____________.
2. Stephanie has a rare blood type that recognizes all surface proteins. She is type _____ blood and can receive blood from anyone, making her a universal _____________.
1.
A father has type AB blood. A mother is heterozygous for type B blood.
A. Parent Genotypes ___________ x ___________
B.
C. What chance do they have of having a child with type A blood? _________
D. What chance do they have of having a child with type B blood? _________
E. What chance do they have of having a child with type AB blood? _________
F. Is it possible for any of the children to receive blood from their father? _________ Why or why not?
__________________________________________________________________________________
__________________________________________________________________________________
______________________________________________________________________
2.
A father has type O blood. A mother is homozygous for type B blood.
A. Parent Genotypes ___________ x ___________
B.
C. What chance do they have of having a child with type B blood? _____
D. If the father becomes injured and needs a blood transfusion will he be able to receive blood from his wife?
His child? Explain.
__________________________________________________________________________________
__________________________________________________________________________
G. If one of their children become injured which parent would they be able to receive blood from? Why?
______________________________________________________________________________

3.
A father has type AB blood. A mother has type AB blood.
A.
Parent Genotypes ___________ x ___________
B
C. What is the couple’s chance of having a child with type AB blood? __________
D. What is the couple’s chance of having a child with type A blood? __________
E. Could the mother receive a blood transfusion from all of her children or only some? Explain
__________________________________________________________________________________
__________________________________________________________________________
4. A father is heterozygous for type A blood. A mother is heterozygous for type B blood.
A.
B
Parent Genotypes ___________ x ___________
C. What is their chance of producing a child with type O blood? _______
D. What is their chance of producing a child with type B blood? _______
E. Could all of the children safely receive a blood transfusion from their mother? Explain
__________________________________________________________________________________
__________________________________________________________________________
5. If Rachel is Type O blood but her mother was type A and her father was type B. Explain how Rachel was able to have her rare type of blood from parents, who both have different blood types than her.
__________________________________________________________________________________
__________________________________________________________________________.
Rachel can receive blood from ( her Mother / her father / neither / both ). Explain
__________________________________________________________________________________
__________________________________________________________________________.
Rachel could give blood to ( her Mother / her father / neither / both ). Explain
__________________________________________________________________________________
__________________________________________________________________________.
6. Timothy’s doctor tells him he has Type B blood. His genotype could be _______ or _______. Timothy has no idea what genotype his parents have. Show 4 possible genotypes his parent could have to give him his Type B blood.
Timothy’s sister has type O blood. Therefore, his parent’s genotype is most likely _____ and _____.
Circle the Punnett Square above that shows this cross.