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Enriching Case Studies with Hands-On Lab:
Blood Typing (continued)
Materials:
• Ward's Science Simulated Blood Typing Kit—I like to have a class set of the blood typing plates and replenish toothpicks
as needed
• From the bulk blood and antisera I can design my own case and buy the blood that is needed to match my case study.
For this case study I used O blood, A blood and B blood
• Ward's Simulated Blood
• Bulk Simulated Blood
• Bulk Antisera
Background Information, Activity Setup:
Blood contains proteins on the surface of the red blood cells called antigens. The antigens serve as a way for the body to self
identify cells. The different types of antigens in blood are A and B. The blood also contains antibodies. The antibodies will bind to
specific antigens. The type of antigens you have will not bind to the antibodies you have in your own blood. For example, A type
blood will have A antigens and B antibodies. If this A blood person receives blood from a type B person, the B antibodies will bind
with the B antigens in the donor's blood. If a person is lacking antigens, that person will have O blood. This person has both types
of antibodies A and B. If a person has AB blood, they have both antigens and no antibodies. The clotting that happens determines
who can donate blood to who.
The clotting can also be used in determining blood type. The blood is placed in a blood typing plate that keeps all the blood in
separate wells. This way the blood can be tested for different antibodies on the same plate. Different antisera is used to mix with
the blood and if it clots that is the type of blood that you have. For example, if it clots in the antisera A and not in the antisera ,
then it is type A blood.
Another antigen on blood is Rhesus factor or Rh. Although there are multiple genes that control Rh presence, it can be
simplified to allele. This is shown by a negative or positive. If a person lacks the antigen for Rh then they are negative and if they
have the factor then they are positive. This can be tested for in the same way as the ABO blood typing.
When looking at inheritance of blood type a punnett square can be used. Blood typing is a multiple allele inheritance. This means
that there are two dominant alleles, A and B. The recessive phenotype is O. The dominant alleles are detonated with
an IA or IB. The recessive allele is denoted by i. This means that IAi and IAIA are both blood type A. IBIB and IBi are both
phenotypically B blood. IAIB is AB blood and ii is O blood. A person positive for Rh has at least one dominant allele and recessive is
a person homozygous negative.
Phenotype Genotypes
+ ++ or + –
– – –
Phenotype Possible Genotypes
A IAIA, IAi
B IBIB, IBi
O ii
AB IAIB
