Project Number: 2023-1-PL01-KA220-SCH-000164042
UNIT 8: Photosynthesis
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Education and Culture Executive Agency (EACEA). Neither the European Union nor EACEA can be held responsible for them.
Introduction
In this activity you will explore how photosynthesis takes place and the factors that affect the rate of photosynthesis.
Source: freepik.com
Learning Outcomes
Student:
- Recognises the importance of photosynthesis in nutrient production in plants.
- Makes inferences about the factors affecting the rate of photosynthesis.
Source: freepik.com
Photosynthesis
- Photosynthesis is a multi-step process that requires sunlight, carbon dioxide, and water as substrates.
- It produces oxygen and glyceraldehyde-3-phosphate (G3P or GA3P), simple carbohydrate molecules that are high in energy and can subsequently be converted into glucose, sucrose, or other sugar molecules.
- These sugar molecules contain covalent bonds that store energy. Organisms break down these molecules to release energy for use in cellular work.
Source: freepik.com
Photosynthesis
Photosynthesis is a complex chemical process in which green plants produce sugar and oxygen for themselves. The equation for photosynthesis is as follows: The plant uses the sugar it produces through photosynthesis to grow and produce more leaves, stems, and roots—the biomass of the plant. The process of photosynthesis, however, does not happen all the time, and when it happens depends on several environmental factors.
Carbon Dioxide (CO2)
Sugar (C6H12O6)
Water (H2O)
Oxygen (O2)
Water (H2O)
Photosynthesis
For example, plants need a supply of water, carbon dioxide, and light energy for photosynthesis to work. Plants must get these resources from the surrounding environment. The process of photosynthesis can also slow down or speed up depending on environmental conditions. In this lab investigation, you will explore how different environmental conditions affect how quickly photosynthesis takes place within a plant. You will then develop a conceptual model that explains why.
Source: freepik.com
Photosynthesis
The energy from sunlight drives the reaction of carbon dioxide and water molecules to produce sugar and oxygen, as seen in the chemical equation for photosynthesis. Though the equation looks simple, it is carried out through many complex steps. Before learning the details of how photoautotrophs convert light energy into chemical energy, it is important to become familiar with the structures involved.
FPhotosynthesis: Photosynthesis uses solar energy, carbon dioxide, and water to produce energy-storing carbohydrates. Oxygen is generated as a waste product of photosynthesis
Photosynthesis and the leaf
In plants, photosynthesis generally takes place in leaves, which consist of several layers of cells. The process of photosynthesis occurs in a middle layer called the mesophyll. The palisade layer contains most of the chloroplast and principal region in which photosynthesis is carried out. The airy spongy layer is the region of storage and gas exchange.
Figure 2: Structure of a leaf (cross-section)
Photosynthesis and the leaf
The gas exchange of carbon dioxide and oxygen occurs through small, regulated openings called stomata (singular: stoma), which also play a role in the plant’s regulation of water balance. The stomata are typically located on the underside of the leaf, which minimizes water loss. Each stoma is flanked by guard cells that regulate the opening and closing of the stomata by swelling or shrinking in response to osmotic changes.
Figure 2: Structure of a leaf (cross-section)
Photosynthesis and the leaf
Scan the QR code on the side to get to know the photosynthesis and the leaf better.
Let's Explore Together
Research Question: How do temperature and light intensity affect the rate of photosynthesis in plants? Your Task: Design a series of experiments to determine how temperature and light intensity affect the rate of photosynthesis in spinach. Then develop a conceptual model that explains why these environmental factors affect the rate of photosynthesis in the way that they do.
Source: freepik.com
Let's Explore Together
Getting Started The first step in developing your model is to design and carry out a series of experiments to determine how temperature and light intensity affect the rate of photosynthesis. You will therefore need a way to calculate a rate of photosynthesis. A photosynthesis rate can be calculated by measuring how much CO2 a plant consumes or how much O2 a plant produces over time using the following equation: Photosynthesis rate = (change in CO2 or O2 level) / time
Source: freepik.com
Let's Explore Together
Observation
Scan the QR code to carry out the experiment. There is a plant inside a sealed flask with a CO2 gas sensor or O2 gas sensor. Observe the change in photosynthesis rate by changing the temperature and light color variables in an AR environment.
Let's Explore Together
The next step is to think about how you will collect the data and how you will analyze it.
To determine how you will collect your data, think about the following questions:
- What will serve as a control (or comparison) condition?
- What will serve as the treatment condition(s)? (Hint: To investigate the effect of temperature on photosynthesis rate, you will need to determine how to vary the temperature inside the flask. To investigate the effect of light intensity on photosynthesis rate, you can use lightbulbs with different wattages.)
- How will you make sure that your data are of high quality (i.e., how will you reduce error)?
- How will you keep track of the data you collect and how will you organize the data?
Source: freepik.com
Let's Explore Together
To determine how you will analyze your data, think about the following questions:
- How will you determine if there is a difference between the treatment and the control conditions?
- What type of calculations will you need to make?
- What type of graph could you create to help make sense of your data?
Once you have carried out your series of experiments, your group will need to develop a conceptual model. Your model needs to explain why these two environmental factors affect the rate of photosynthesis in the way that they do. The model should also explain what is happening at the submicroscopic level during the process of photosynthesis. Once your group has finished collecting and analyzing your data, prepare an argumentation session that you can use to share your initial argument.
Source: freepik.com
Argumentation session: Information for the teacher
- Once each group has finished collecting and analyzing your data, prepare an argumentation session that students can use to share their initial argument (short presentations).
- The goal of the argumentation session is not to convince others that your argument is the best one; rather, the goal is to identify errors or instances of faulty reasoning in the arguments so these mistakes can be fixed.
- You will therefore need to evaluate the content of the claim, the quality of the evidence used to support the claim, and the strength of the justification of the evidence included in each argument that you see.
Source: freepik.com
Argumentation session: Information for the teacher
In order to critique an argument, you will need more information. You might, therefore, need to ask the presenter one or more follow-up questions, such as:
- How did you collect your data? Why did you use that method? Why did you collect those data?
- What did you do to analyze your data? Why did you decide to do it that way? Did you check your calculations? Is that the only way to interpret the results of your analysis? How do you know that your interpretation of your analysis is appropriate?
- What other claims did your group discuss before you decided on that one? Why did your group abandon those alternative ideas?
- How confident are you that your claim is valid? What could you do to increase your confidence?
Source: freepik.com
Argumentation session: Information for the teacher
Once the argumentation session is complete, students will have a chance to discuss with their groups and revise your original argument. Groups might need to gather more data or design a way to test one or more alternative claims as part of this process. Remember, your goal at this stage of the investigation is to develop the most valid or acceptable answer to the research question! (Why Do Temperature and Light Intensity Affect the Rate of Photosynthesis in Plants?)
Source: freepik.com
Report: Information for the teacher
Once you have completed your research, you can ask students to prepare an investigation report that consists of three sections that provide answers to the following questions:
- What question were you trying to answer and why?
- What did you do during your investigation and why did you conduct your investigation in this way?
- What are your results and arguments?
Your report should answer these questions in two pages or less. This report should be typed, and any diagrams, figures, or tables should be embedded into the document.
Source: freepik.com
UNIT 8: Photosynthesis
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Transcript
Project Number: 2023-1-PL01-KA220-SCH-000164042
UNIT 8: Photosynthesis
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Education and Culture Executive Agency (EACEA). Neither the European Union nor EACEA can be held responsible for them.
Introduction
In this activity you will explore how photosynthesis takes place and the factors that affect the rate of photosynthesis.
Source: freepik.com
Learning Outcomes
Student:
Source: freepik.com
Photosynthesis
Source: freepik.com
Photosynthesis
Photosynthesis is a complex chemical process in which green plants produce sugar and oxygen for themselves. The equation for photosynthesis is as follows: The plant uses the sugar it produces through photosynthesis to grow and produce more leaves, stems, and roots—the biomass of the plant. The process of photosynthesis, however, does not happen all the time, and when it happens depends on several environmental factors.
Carbon Dioxide (CO2)
Sugar (C6H12O6)
Water (H2O)
Oxygen (O2)
Water (H2O)
Photosynthesis
For example, plants need a supply of water, carbon dioxide, and light energy for photosynthesis to work. Plants must get these resources from the surrounding environment. The process of photosynthesis can also slow down or speed up depending on environmental conditions. In this lab investigation, you will explore how different environmental conditions affect how quickly photosynthesis takes place within a plant. You will then develop a conceptual model that explains why.
Source: freepik.com
Photosynthesis
The energy from sunlight drives the reaction of carbon dioxide and water molecules to produce sugar and oxygen, as seen in the chemical equation for photosynthesis. Though the equation looks simple, it is carried out through many complex steps. Before learning the details of how photoautotrophs convert light energy into chemical energy, it is important to become familiar with the structures involved.
FPhotosynthesis: Photosynthesis uses solar energy, carbon dioxide, and water to produce energy-storing carbohydrates. Oxygen is generated as a waste product of photosynthesis
Photosynthesis and the leaf
In plants, photosynthesis generally takes place in leaves, which consist of several layers of cells. The process of photosynthesis occurs in a middle layer called the mesophyll. The palisade layer contains most of the chloroplast and principal region in which photosynthesis is carried out. The airy spongy layer is the region of storage and gas exchange.
Figure 2: Structure of a leaf (cross-section)
Photosynthesis and the leaf
The gas exchange of carbon dioxide and oxygen occurs through small, regulated openings called stomata (singular: stoma), which also play a role in the plant’s regulation of water balance. The stomata are typically located on the underside of the leaf, which minimizes water loss. Each stoma is flanked by guard cells that regulate the opening and closing of the stomata by swelling or shrinking in response to osmotic changes.
Figure 2: Structure of a leaf (cross-section)
Photosynthesis and the leaf
Scan the QR code on the side to get to know the photosynthesis and the leaf better.
Let's Explore Together
Research Question: How do temperature and light intensity affect the rate of photosynthesis in plants? Your Task: Design a series of experiments to determine how temperature and light intensity affect the rate of photosynthesis in spinach. Then develop a conceptual model that explains why these environmental factors affect the rate of photosynthesis in the way that they do.
Source: freepik.com
Let's Explore Together
Getting Started The first step in developing your model is to design and carry out a series of experiments to determine how temperature and light intensity affect the rate of photosynthesis. You will therefore need a way to calculate a rate of photosynthesis. A photosynthesis rate can be calculated by measuring how much CO2 a plant consumes or how much O2 a plant produces over time using the following equation: Photosynthesis rate = (change in CO2 or O2 level) / time
Source: freepik.com
Let's Explore Together
Observation
Scan the QR code to carry out the experiment. There is a plant inside a sealed flask with a CO2 gas sensor or O2 gas sensor. Observe the change in photosynthesis rate by changing the temperature and light color variables in an AR environment.
Let's Explore Together
The next step is to think about how you will collect the data and how you will analyze it.
To determine how you will collect your data, think about the following questions:
Source: freepik.com
Let's Explore Together
To determine how you will analyze your data, think about the following questions:
- How will you determine if there is a difference between the treatment and the control conditions?
- What type of calculations will you need to make?
- What type of graph could you create to help make sense of your data?
Once you have carried out your series of experiments, your group will need to develop a conceptual model. Your model needs to explain why these two environmental factors affect the rate of photosynthesis in the way that they do. The model should also explain what is happening at the submicroscopic level during the process of photosynthesis. Once your group has finished collecting and analyzing your data, prepare an argumentation session that you can use to share your initial argument.Source: freepik.com
Argumentation session: Information for the teacher
Source: freepik.com
Argumentation session: Information for the teacher
In order to critique an argument, you will need more information. You might, therefore, need to ask the presenter one or more follow-up questions, such as:
Source: freepik.com
Argumentation session: Information for the teacher
Once the argumentation session is complete, students will have a chance to discuss with their groups and revise your original argument. Groups might need to gather more data or design a way to test one or more alternative claims as part of this process. Remember, your goal at this stage of the investigation is to develop the most valid or acceptable answer to the research question! (Why Do Temperature and Light Intensity Affect the Rate of Photosynthesis in Plants?)
Source: freepik.com
Report: Information for the teacher
Once you have completed your research, you can ask students to prepare an investigation report that consists of three sections that provide answers to the following questions:
- What question were you trying to answer and why?
- What did you do during your investigation and why did you conduct your investigation in this way?
- What are your results and arguments?
Your report should answer these questions in two pages or less. This report should be typed, and any diagrams, figures, or tables should be embedded into the document.Source: freepik.com