Lesson plan of Photosynthesis

Objectives (5 - 10 minutes)

1. Understanding Photosynthesis: Students must be able to define the photosynthesis process, identifying the components involved, the process steps, and the chemical reactions that occur.

2. Relationship between Photosynthesis and Life on Earth: Students must understand how photosynthesis is essential for life on Earth, differentiating between photosynthesis by plants and algae and photosynthesis by photosynthesizing bacteria.

3. Applying Knowledge about Photosynthesis: Students must be able to apply the acquired knowledge about photosynthesis to solve problems and answer questions related to it.

Secondary objectives:

• Critical Thinking Development: In addition to acquiring knowledge, students should be encouraged to develop critical thinking about photosynthesis and its impacts on the environment and human life.

• Stimulation of Research and Autonomous Learning: Class should stimulate students to seek information beyond what is presented in class, promoting autonomous learning and research as learning tools.

Introduction (10 - 15 minutes)

1. Review of Previous Content: The teacher should recall the concepts of the cell, organelles, mitochondria, and chloroplasts, highlighting their importance for studying photosynthesis. This review can be done quickly, using questions directed at students to check how much they remember the previous concepts.

2. Problem Situation 1: "Why are plants green?" The teacher should introduce the question of why plants are green, leading students to think about the relationship between the color of plants and photosynthesis. This question serves to pique students' curiosity and prepare them for the content that will be covered.

3. Problem Situation 2: "What would happen if there was no photosynthesis?" The teacher should propose imagining a world without photosynthesis, leading students to think about the consequences of this for life on Earth. This problem situation aims to demonstrate the importance of photosynthesis and arouse students' interest in the subject.

4. Contextualization: The teacher should explain that photosynthesis is a process that occurs in all plants and some bacteria and is the basis for the production of oxygen in the atmosphere and food for most living beings. In addition, you can cite examples of how photosynthesis is present in everyday life, such as in solar energy production and in artificial photosynthesis.

5. Topic Introduction: The teacher should introduce the topic of the class, explaining that photosynthesis is the process by which plants, algae, and some bacteria use light energy to produce sugars from carbon dioxide and water. In addition, mention that photosynthesis is responsible for the green color of plants because chlorophyll, the pigment responsible for capturing light, is green and reflects this color.

6. Curiosity 1: "Did You Know? The oxygen we breathe is produced by photosynthesis!" The teacher should share this surprising information, explaining that photosynthesis is the main source of oxygen in the atmosphere, without which, there would be no life as we know it on Earth.

7. Curiosity 2: "Did You Know? Photosynthesis is so efficient that if all the world's plants stopped performing this process, it would take thousands of years for the amount of oxygen in the atmosphere to run out!" The teacher should share this curiosity, emphasizing the importance of photosynthesis for maintaining life on Earth.

Development (20 - 25 minutes)

1. Photosynthesis Theory (10 - 15 minutes): 1.1. What is Photosynthesis? The teacher should explain that photosynthesis is the process by which plants, algae, and some bacteria use light energy to produce sugars from carbon dioxide and water. In addition, it should emphasize that photosynthesis is the process that sustains life on Earth, as it is responsible for the production of oxygen and most of the food. 1.2. Chemical Equation for Photosynthesis The teacher should present the chemical equation for photosynthesis (6CO2 + 6H2O + light -> C6H12O6 + 6O2), explaining that carbon dioxide and water are transformed into glucose and oxygen in the presence of light. 1.3. Stages of Photosynthesis The teacher should explain the two stages of photosynthesis: the light phase and the dark phase. In the light phase, light energy is captured by chlorophyll and used to break water into oxygen and hydrogen. In the dark phase, hydrogen and carbon dioxide are used to produce glucose. 1.4. Importance of Chlorophyll The teacher should explain that chlorophyll is the pigment that gives plants their green color and is responsible for capturing light energy. In addition, it should be emphasized that without chlorophyll, photosynthesis would not be possible.

2. Difference Between Photosynthesis in Plants and Bacteria (5 - 7 minutes): 2.1. Photosynthesis in Plants The teacher should explain that most plants perform photosynthesis in the presence of light through structures called chloroplasts, found primarily in the leaves. In addition, it should emphasize that plants produce oxygen and store glucose as energy. 2.2. Photosynthesis in Bacteria The teacher should explain that some bacteria, such as cyanobacteria, also perform photosynthesis, but in a different way than plants. They do not have chloroplasts, but instead, have photosynthetic pigments in the cell membrane. In addition, it should be emphasized that photosynthesizing bacteria do not produce oxygen, but instead, produce other substances, such as sulfur.

3. Resolution of Problem Situations (5 - 7 minutes): 3.1. Why are plants green? The teacher should explain that the green color of plants is due to chlorophyll, which reflects green light. The other colors of the spectrum (blue and red) are absorbed by chlorophyll and used in photosynthesis. 3.2. What would happen if there were no photosynthesis? The teacher should explain that without photosynthesis, there would be no production of oxygen and most living beings would have no food to survive, as photosynthesis is the basis of the food chain.

4. Knowledge Application (3 - 5 minutes): The teacher should ask students to think of other examples of how photosynthesis is present in their lives, such as in solar energy production and in artificial photosynthesis. In addition, you can ask students to research more about photosynthesis at home and bring their findings to the next class.

Feedback (10 - 15 minutes)

1. Group Discussion (5 - 7 minutes): The teacher should promote a group discussion, where students are encouraged to share their responses and reflections on the issues presented during class. This is an opportunity for students to express their opinions, clarify doubts, and learn from each other. The teacher should guide the discussion, ensuring that all students have a chance to participate.

   1.1. Problem Situation 1: "Why are plants green?" The teacher should ask students if they managed to come up with an answer to this question, and if so, what their conclusions were. The teacher may point out that the green color of plants is due to chlorophyll, which reflects green light, while the other colors of the spectrum (blue and red) are absorbed and used in photosynthesis.

   1.2. Problem Situation 2: "What would happen if there were no photosynthesis?" The teacher should ask students what they think would happen if there were no photosynthesis. The teacher may reinforce that photosynthesis is essential for life on Earth, as it produces oxygen and food, and without it, most living beings would have no way to survive.

2. Connection with the Theory (2 - 3 minutes): The teacher should make the connection between the group discussion and the theory presented. The teacher may highlight how the students' answers align with the concepts of photosynthesis, the importance of chlorophyll, and the relationship between photosynthesis and life on Earth. In addition, the teacher can take this opportunity to clarify any doubts that may have arisen during the discussion.

3. Individual Reflection (3 - 5 minutes): The teacher should suggest that students reflect individually on what they have learned during class. The teacher may ask questions such as:

   3.1. What was the most important concept you learned today? The teacher should encourage students to think about what they consider to be the main point of the class, which can help reinforce learning.

   3.2. What questions have not yet been answered? The teacher should encourage students to identify any questions they may still have, so that they can be addressed in future classes.

4. Feedback (1 - 2 minutes): The teacher should conclude the class by asking students for feedback on the class. The teacher may ask what they liked about the class, what they found most challenging, and what could be improved. This can help the teacher adjust future classes according to students' needs and interests.

Conclusion (5 - 7 minutes)

1. Summary and Review (2 - 3 minutes): The teacher should make a brief summary of the main points covered in class, reinforcing the concepts of photosynthesis, the importance of chlorophyll, the process steps, and the chemical reactions involved. In addition, it should recap the difference between photosynthesis by plants and bacteria. The teacher may also review the proposed problem situations, highlighting students' responses and reflections.

2. Connection Between Theory and Practice (1 - 2 minutes): The teacher should explain how the class connected theory, practice, and knowledge applications. The teacher may highlight how the theory of photosynthesis was presented in a clear and didactic way, and how the problem situations and group discussion helped students apply the acquired knowledge. In addition, mention how the class stimulated critical thinking and research as learning tools.

3. Supplementary Materials (1 - 2 minutes): The teacher should suggest additional materials for students who want to deepen their knowledge of photosynthesis. These materials can include books, articles, videos, and educational websites. The teacher may also propose practical activities, such as conducting a photosynthesis experiment at home or researching a related topic, such as artificial photosynthesis.

4. Relevance of the Subject (1 minute): Finally, the teacher should reinforce the importance of the subject for the students' daily lives and for the world in general. The teacher may emphasize that photosynthesis is one of the most essential processes for life on Earth, as it is the basis for the production of oxygen and food. In addition, mention how understanding photosynthesis can help explain natural phenomena, such as the changing seasons, and technological applications, such as solar energy and artificial photosynthesis.