Learning aims: |
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Students should understand the laws of heredity of blood types. They should be able to explain that it is the presence of antigens and their antibodies that is inherited. It is inherited from both parents. Each person has two alleles of a blood type gene – one is from the father, the other from the mother when only one of each parent’s is randomly given to the child. That is why siblings can have different blood types and blood type of children can be identical with that of their mother or their father but it does not have to be. |
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Materials: |
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calculators for determining possible blood type of a child based on the information about parents‘ blood types (find on the Internet), matches of 2 colours |
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Suggestions for use: |
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Tell the students to open the calculator* and try to design some examples. Then ask them, to explain how heredity of blood types relates to what they have found out about them in connection with transfusion. Ask the students to model genes of blood types using the matches: antigen A present – red head, antigen B present – blue head, no antigen – broken head Every gene consists of two matches – gene parts (called allele). One comes from the mother, the other from the father. In case of blood types both alleles manifest themselves together and the result is a blood type A, B, AB or 0. What alleles did a man with the blood type AB inherit from his parents? Ask students to make a table in which they show heredity of blood types by means of AB0 system. They can work individually and then compare their result with others. Suggested table:
Exercise: Erika has a blood type A and she has had a baby with a blood type AB. She appointed Pavol, who has a blood type 0, as the father. Can Pavol really be the father of Erika’s child Students have an opportunity to discover combinations of parents’ blood type, when a child is born with blood type 0, and explain why a child may have blood type 0 when both parents have blood type A. * Calculator examples: http://www.babymed.com/tools/blood-type-calculator http://www.pediatriconcall.com/fordoctor/pedcalc/blood_group_detection.aspx |
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Possible questions: |
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