Objectives (5 - 7 minutes)

1. Understand the ABO Blood Group System: Students should be able to understand the basis of the ABO blood group system, including the presence of A and B antigens and anti-A and anti-B antibodies in different blood types.

2. Master the Concepts of Genetic Inheritance and Multiple Alleles: Students should be able to explain how the genes that determine blood groups are transmitted from generation to generation, understanding the concept of multiple alleles and how they determine different blood types.

3. Solve Blood Group Inheritance Problems: Students should be able to apply their knowledge to solve blood group inheritance problems, determining the possible blood types for parents and children.

   Secondary Objectives:

   • Develop Critical Thinking: By solving genetic inheritance problems, students will have the opportunity to develop critical thinking skills, learning to analyze information and come to logical conclusions.

   • Promote Active Learning: The expository lesson will be complemented with practical and interactive activities, encouraging students to actively engage in the learning process.

Introduction (10 - 15 minutes)

1. Review of Previous Content: The teacher should start the lesson by briefly reviewing basic genetics concepts, especially those related to heredity and the transmission of genetic traits. This includes a recap of genes, chromosomes, DNA, and alleles. (2 - 3 minutes)

2. Presentation of Problem Situations: Next, the teacher should present two problem situations to pique the students' interest:

   • The first one may involve determining the possible blood groups of a family based on the parents' blood types. For example, if a father has blood type A and the mother has blood type B, what are the possible blood groups for their children?

   • The second situation could be a hypothetical scenario where a baby is found abandoned, and doctors need to determine the blood type to ensure a safe transfusion. (3 - 5 minutes)

3. Contextualization and Importance of the Subject: The teacher should then contextualize the importance of studying blood groups, explaining how this information is used in real situations such as blood transfusions, organ transplants, and paternity tests. Additionally, it should be highlighted that understanding blood groups is crucial for forensic genetics, where the analysis of blood samples can help solve crimes. (2 - 3 minutes)

4. Introduction to the Topic: To introduce the topic and capture the students' attention, the teacher can share some curiosities and interesting facts about blood groups. For example:

   • Despite there being over 30 types of human blood group systems, the ABO system is the most important in medicine. (1 minute)

   • The discovery of the ABO system by Karl Landsteiner in 1901 earned him the Nobel Prize in Medicine in 1930. (1 minute)

   • Blood type AB is considered the 'universal recipient' as it can receive blood from any type, while blood type O is the 'universal donor' as it can donate blood to any type. However, these rules have some exceptions, and the teacher can question the students about why this happens. (2 - 3 minutes)

Development (20 - 25 minutes)

1. Theory: ABO System (5 - 7 minutes): The teacher should start by explaining the ABO system, which is the most important for medicine. This includes the presence of A and B antigens and anti-A and anti-B antibodies in different blood types. The teacher should emphasize that blood type is determined by genes inherited from parents and that there are three types of alleles for the ABO system: A, B, and O. Students should be encouraged to ask questions and actively participate in the discussion.

2. Theory: Genetic Inheritance and Multiple Alleles (5 - 7 minutes): Next, the teacher should explain how genetic inheritance works in the ABO system. This includes the idea that an individual can inherit an A, B, or O allele from each parent. The teacher should explain that the A allele is dominant over the O allele, and the B allele is dominant over the O allele, but the A and B alleles are co-dominant. This means that if an individual inherits an A allele from the father and a B allele from the mother, they will have the AB blood type.

3. Practical Activity: Card Game (8 - 10 minutes): After the theoretical explanation, students should be divided into groups of 3 to 4 people. Each group will receive a set of cards, each representing an A, B, or O allele. The students should then 'cross' the cards, combining one allele from each parent to determine the blood type of the 'child'. The teacher should move around the room, assisting the groups as needed and clarifying any doubts.

4. Practical Activity: Problem Solving (2 - 3 minutes): After the card game, the teacher should provide students with some blood group inheritance problems to solve individually. This will allow students to apply what they have learned in a more challenging way. The teacher should review the answers with the class, ensuring that everyone understands how to arrive at the correct answer.

5. Theory Review and Practical Activities (3 - 5 minutes): Finally, the teacher should review the key points of the theory and practical activities. This includes a recap of the ABO system, the importance of multiple alleles in blood group inheritance, and a review of the steps to solve blood group inheritance problems. Students should be encouraged to ask questions and clarify any doubts they may have.

Return (8 - 10 minutes)

1. Group Discussion (3 - 5 minutes): The teacher should promote a group discussion on the solutions found by students for blood group inheritance problems. Each group should share their answers and explain how they arrived at them. The teacher should encourage students to question and respond to each other, promoting a collaborative learning environment.

2. Theory-Practice Connection (2 - 3 minutes): After the group discussion, the teacher should review the connections between the presented theory and the practical activities carried out. This includes explaining how the allele cards represent genetic inheritance in the ABO system, and how blood group inheritance problems were solved using the concepts of multiple alleles and dominance.

3. Individual Reflection (3 - 5 minutes): The teacher should then ask students to reflect individually on what they learned in the lesson. To assist in this reflection, the teacher can ask the following questions:

   1. What was the most important concept you learned today?
   2. What questions have not been answered yet?
   3. How can you apply what you learned about blood groups in real life?

   Students should be encouraged to write down their answers, which can be shared with the class if desired. This individual reflection will help students consolidate what they have learned and identify any areas where they still have doubts.

4. Closure (1 minute): To end the lesson, the teacher should emphasize the importance of studying blood groups, reiterating the practical applications that were discussed during the lesson. The teacher should also inform students about what will be covered in the next lesson, preparing them for the next topic of study.

Conclusion (5 - 7 minutes)

1. Summary of Contents (2 - 3 minutes): The teacher should start the Conclusion by recapping the key points of the lesson. This includes explaining the ABO blood group system, the genetic inheritance of blood groups, and the resolution of blood group inheritance problems. The teacher can ask students to share what they consider the most important points of the lesson, thus reinforcing what was learned.

2. Connection between Theory, Practice, and Applications (1 - 2 minutes): Next, the teacher should reiterate the importance of the practical activities carried out during the lesson for understanding the theoretical concepts. The teacher should highlight how solving blood group inheritance problems allowed students to apply their knowledge in a practical and meaningful way. Additionally, the teacher should recall the real-world applications of blood groups, such as determining blood type for blood transfusions and organ transplants.

3. Extra Materials (1 - 2 minutes): The teacher should suggest some additional materials for students who wish to deepen their understanding of the topic. This may include reference books, explanatory videos online, educational websites, and interactive genetics games. For example, the teacher may suggest the use of online simulators that allow students to experiment with blood group inheritance.

4. Importance of the Topic (1 minute): Finally, the teacher should emphasize the relevance of the topic to everyday life. It should be highlighted again how understanding blood groups is crucial in various contexts, from medicine (blood transfusions, organ transplants) to forensic genetics. The teacher should encourage students to apply what they have learned by observing the blood types of their families and friends, and reflecting on the practical implications of the topic.