Title: Inheritance of blood groups, Rh inheritance

Target group

8th‑grade students of elementary school.

Core curriculum

General requirements

I. Knowledge of biological diversity and basic biological phenomena and processes. Pupil:

2. explains biological phenomena and processes occurring in selected organisms and in the environment.

Specific requirements

V. Genetics. Student:

9. explains the inheritance of human blood groups (AB0 system, Rh factor).

The general aim of education

Pupils discuss rules regarding the inheritance of blood group and Rh factor.

Criteria for success

• discuss the manner in which the human blood group is conditioned in the AB0 system;

• you will explain what the Rh factor is;

• you define the concept of a serological conflict;

• based on your parents' genotypes, you can determine which blood groups your children can have;

• you will explain why knowledge of the blood group and the Rh factor is important when you need blood transfusions or some organ transplants.

Key competences

• communicating in the mother tongue;

• communicating in a foreign language;

• Mathematical competence and basic competences in science and technology; 

• digital competence;

• learning to learn;

• Social and civic competences.

Methods/forms of work:

Work with text, snowball method.

Individual work, work in pairs, group work.

Teaching measures:

• abstract;

• interactive whiteboard or traditional blackboard;

• tablets/computers;

Lesson phases

Introduction

1. The teacher gives the subject and the purpose of the lesson in a language that the student understands as well as the criteria for success. Ask students what they know about blood inheritance.

2. The teacher gives the topic of the lesson, the students write it in their notebooks.

3. The teacher reminds students about antigens and agglutinins.

Realization

1. The lecturer discusses the genotypes that condition blood groups (including the Rh factor) and the frequency of occurrence of particular blood groups in Poland.

2. Pupils who know their blood group write it on unsigned person cards and throw it into a ballot box. The selected students count the pages for each blood group separately and present the results. Students estimate the percentage of blood groups in the class, and then compare the results of their calculations with the percentage distribution of blood groups in Poland.

3. The teacher explains why you should make note your blood group: in an emergency, it’s knowledge makes it easier to become a donor or recipient of blood, some tissues or organs. The lecturer presents an interactive illustration showing information on the compatibility of individual blood groups.

4. The teacher informs that in some cases, determining the blood group of the alleged child's father allows to rule out his fatherhood. Knowledge about the Rh factor of future parents can also be an important piece of information that allows to apply preventive measures against the occurrence of a serological conflict between the mother and the unborn child.

5. Students, working in pairs, perform „Command 1” and „Command 2”. The teacher monitors the work of the pupils, and helps them in case of difficulties.

6. Students independently solve interactive exercises that consolidate knowledge gained during the lesson.

Summary

Students ask questions, ask for additional explanations and complete their notes.

Homework

Look for information about honorary blood donors at home.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Inheritance of blood groups, Rh inheritance

Quite often, one gene has more than two alleles. Alleles present in more than two forms are called multiple alleles. A good example of a gene having several varieties is a gene that determines blood groups in humans. It occurs in three alleles: IIndeks górny A^A, IIndeks górny B^B, i. The first two, as indicated by the record, are the dominant alleles, and the third - the recessive allele. In addition, alleles IIndeks górny A^A, IIndeks górny B^B they are equal to each other, which means that one does not dominate the other. Each man inherits only two alleles conditioning a specific blood group: one after father and the other after mother.

In ABO system four blood types occur: A, B, AB and O.

Blood group O is conditioned by genotype ii and group AB by genotype IIndeks górny A^AIIndeks górny B^B. Groups A and B can be determined by two genotypes. A person with blood group B may have a genotype IIndeks górny B^BIIndeks górny B^Bor IIndeks górny B^Bi. Another, with group A, may have a genotype IIndeks górny A^A IIndeks górny A^A or IIndeks górny A^A i . To predict blood groups of the offspring, genetic crosses should be written.

Rh factor is a substance, also called D antigen, appearing on the surface of erythrocytes in 85% of people. In humans, the gene in two variants corresponds to the inheritance of the Rh factor: Rh+ i Rh-. The Rh+ allele is the dominant allele and the Rh- allele is the recessive allele. Accordingly, people who have the Rh+ Rh+ or Rh+ Rh- genotype have Rh factor (D antigen) on the surface of the erythrocytes and people who have the Rh‑Rh- genotype don't have Rh factor.

The offspring of a man who is heterozygous with the Rh + blood group and a woman with the Rh- blood group may have Rh+ or Rh- blood groups. If the Rh factor is incompatible between the mother and her unborn child, i.e. when the Rh‑mother's child, inherits the Rh+ from the father, it results in a serological conflict.

It only happens when the mother is a Rh‑recessive homozygote. When a father gives Rh+ to his child, their child will be heterozygous, which means that a Rh factor will appear in his blood.

It is worth noting your blood group. Adults who know theirs can respond to calls for specific blood groups, especially rare ones. On the basis of the knowledge of the principles of inheritance of blood groups, paternity can be excluded in some cases.

• Most human traits are conditioned by a set of many genes that occur in the form of two or more alleles.

• Few human traits inherit monogenes (they are conditioned by one gene that can exist in two or more alleles); belong to them, among others blood group and Rh factor.

• Blood groups in the ABO system are conditioned by the presence of two of the three alleles: I Indeks górny A  Indeks górny koniec^A , I Indeks górny B  Indeks górny koniec^B  and i.

• The presence of the Rh factor in human blood depends on two alleles: the dominant allele – Rh+ and the recessive allele – Rh-.