Standards Alignment
- MS-LS1-7 primary
Develop a model to describe how food is rearranged through chemical reactions forming new molecules that support growth and/or release energy as this matter moves through an organism.
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Lesson Overview
In this Grade 7 science lesson, students explore how food molecules are chemically rearranged inside organisms to form new molecules that support growth or release energy. Through developing and using models, students describe the chemical processes that break down food and build new molecules, emphasizing that atoms are conserved and energy is released during these reactions. This lesson aligns with NGSS standard MS-LS1-7 and is part of the Life Sciences theme focusing on Matter and Energy in Organisms and Ecosystems.
Learning Objectives
- Develop a model to describe how food molecules are broken down and rearranged through chemical reactions inside an organism.
- Explain how these chemical reactions form new molecules that support growth or release energy.
- Describe that atoms are conserved during these chemical reactions, meaning matter is neither created nor destroyed.
- Use evidence from models or observations to support explanations about matter and energy flow in organisms.
Success Criteria
- Students can create a model showing the breakdown and rearrangement of food molecules inside an organism.
- Students can explain how the new molecules formed support growth or provide energy.
- Students understand and can describe that atoms are conserved during these chemical reactions.
- Students use scientific reasoning and evidence to justify their models and explanations.
Prerequisite Knowledge
Students should understand basic concepts of molecules and atoms, and have some familiarity with chemical reactions as processes that rearrange atoms to form new substances. Prior knowledge of energy flow in ecosystems and the role of food as a source of matter and energy is helpful.
Key Vocabulary
- Chemical reaction
- Molecule
- Atom
- Food molecule
- Energy release
- Growth
- Model
- Conservation of matter
Materials and Resources
- Diagram or animation showing chemical reactions in digestion or cellular respiration
- Modeling materials (e.g., molecular model kits, colored balls and sticks)
- Chart paper or whiteboard for drawing models
- Student notebooks or science journals
Teacher Preparation
- Review NGSS standard MS-LS1-7 and related disciplinary core ideas about matter and energy in organisms.
- Prepare or select a clear visual model or animation illustrating how food molecules are broken down and rearranged chemically inside organisms.
- Gather materials for student modeling activities.
- Prepare guiding questions to prompt student thinking about conservation of matter and energy release during chemical reactions.
Detailed Lesson Notes
Chemical Reactions in Organisms
Chemical reactions inside organisms break down food molecules into smaller parts and rearrange atoms to form new molecules. These new molecules can be used to build parts of the organism (supporting growth) or to release energy needed for life processes. For example, complex carbohydrates are broken down into simpler sugars, which can then be used to build other molecules or provide energy.
Conservation of Matter in Chemical Reactions
During these chemical reactions, atoms are neither created nor destroyed; they are simply rearranged. This means the total amount of matter stays the same even though the molecules change. Understanding this conservation of matter helps explain how food is transformed inside organisms.
Energy Release and Use
When food molecules are broken apart and rearranged, energy stored in chemical bonds is released. Organisms use this energy to perform activities such as movement, growth, and repair. Some of the energy is stored in new molecules that help the organism grow.
Developing and Using Models
Models help students visualize and explain the chemical processes inside organisms. A model might show food molecules being broken down into smaller molecules and then rearranged into new molecules. Students can use physical models, drawings, or digital animations to represent these processes and explain how matter and energy flow through the organism.
Worked Examples
Worked Example 1
Scenario
A student models the breakdown of a carbohydrate molecule into glucose and then shows glucose being rearranged to form new molecules that help cells grow. Explain why the total number of atoms remains the same in the model even though the molecules look different.
Explanation
Atoms are conserved in chemical reactions, meaning they are neither created nor destroyed. The carbohydrate molecule breaks down into glucose molecules, and glucose is then rearranged into new molecules. Although the molecules change, the total number of atoms stays the same because the atoms are simply rearranged, not lost or gained.
Answer Guide
The total number of atoms remains the same because chemical reactions rearrange atoms to form new molecules without creating or destroying atoms.
Engage
Teacher Activity
Show students a simple animation or diagram of food being broken down inside an organism and ask them to observe what happens to the food molecules.
Student Activity
Watch the animation and discuss initial ideas about what happens to the food inside the body.
Explanation
This phase introduces the phenomenon of food molecules changing inside organisms, sparking curiosity and activating prior knowledge.
Examples
- Food molecules appear to be broken down into smaller parts.
- Atoms seem to be rearranged into new molecules.
- Energy might be released or used during the process.
Explore
Teacher Activity
Provide students with molecular model kits or materials to build models of food molecules and how they might be broken down and rearranged.
Student Activity
Work in groups to build models showing the breakdown of a food molecule into smaller parts and the formation of new molecules.
Explanation
Students actively construct models to represent chemical reactions rearranging food molecules, deepening their understanding through hands-on experience.
Examples
- Models show food molecules breaking into smaller molecules.
- Atoms are rearranged but total number of atoms remains the same.
- Models include new molecules that could support growth or release energy.
Explain
Teacher Activity
Lead a class discussion to connect student models to the scientific explanation of chemical reactions in organisms.
Student Activity
Share and explain their models, describing how food molecules are rearranged and how energy is involved.
Explanation
This phase clarifies scientific concepts and terminology, linking student models to the NGSS standard and disciplinary core ideas.
Examples
- Students explain atoms are rearranged, not lost or gained.
- New molecules support growth or energy needs.
- Energy is released when bonds break and stored in new molecules.
- Models reflect conservation of matter.
Elaborate
Teacher Activity
Present a real-world example such as cellular respiration or digestion, showing how chemical reactions rearrange food molecules to release energy and build new molecules.
Student Activity
Analyze the example and refine their models or explanations to include this information.
Explanation
Students apply their understanding to a real biological process, reinforcing and extending their models and explanations.
Examples
- Students identify glucose breakdown and energy release.
- Models include molecules like ATP or building blocks for growth.
- Energy flow is connected to chemical reactions.
Evaluate
Teacher Activity
Ask students to present their final models and explanations, and provide feedback based on scientific accuracy and use of evidence.
Student Activity
Present models and explanations, respond to questions, and reflect on their learning.
Explanation
Assessment of student understanding through their ability to model and explain the chemical rearrangement of food molecules and energy flow.
Examples
- Clear, accurate models showing molecule breakdown and rearrangement.
- Explanations include conservation of matter and energy release.
- Use of evidence from models or examples to support claims.
Classroom Activity
Work in groups to build models showing the breakdown of a food molecule into smaller parts and the formation of new molecules.
Guided Practice
Guided Practice 1
Prompt
What happens to food molecules during chemical reactions inside an organism?
Teacher Answer Guide
Food molecules are broken down and their atoms are rearranged to form new molecules that support growth or release energy.
Guided Practice 2
Prompt
Why are atoms conserved during these chemical reactions?
Teacher Answer Guide
Because atoms are neither created nor destroyed in chemical reactions; they are only rearranged.
Guided Practice 3
Prompt
How is energy involved in the rearrangement of food molecules?
Teacher Answer Guide
Energy is released when chemical bonds in food molecules are broken and can be used by the organism for life processes.
Guided Practice 4
Prompt
What does a model of food molecule rearrangement inside an organism show?
Teacher Answer Guide
It shows food molecules breaking down into smaller parts, atoms being rearranged into new molecules, and energy being released or stored.
Guided Practice 5
Prompt
Why is it important to understand these chemical reactions in organisms?
Teacher Answer Guide
Understanding these reactions explains how organisms grow, get energy, and maintain life by transforming food into useful molecules and energy.
Independent Practice
- Foundational: What is a chemical reaction in the context of food inside an organism?
- Developing: Explain why atoms are conserved during the chemical reactions that rearrange food molecules inside an organism.
- Application: Draw or describe a simple model showing how a food molecule can be broken down and rearranged to release energy and form new molecules that support growth.
- Analysis: Compare two models: one that shows atoms disappearing during digestion and one that shows atoms being rearranged. Which model is scientifically accurate and why?
- Challenge: Explain how the energy released from breaking down food molecules is used by an organism, and why this process is important for growth and survival.
Independent Practice Teacher Answer Key
- 1. A chemical reaction is a process where food molecules are broken down and rearranged to form new molecules inside an organism.
- 2. Atoms are conserved because they are not created or destroyed during chemical reactions; they are only rearranged to form new molecules.
- 3. A model shows a large food molecule breaking into smaller parts, with atoms rearranged into new molecules. Energy is released when bonds break, and new molecules can be used for growth or energy storage.
- 4. The model showing atoms being rearranged is accurate because atoms are conserved in chemical reactions. Atoms cannot disappear; they only change how they are connected.
- 5. Energy released from breaking down food molecules powers cellular activities like movement, repair, and building new molecules. This energy is essential for growth and survival because it fuels all life processes.
Guiding Questions
- What happens to food molecules inside an organism?
- How are atoms rearranged during chemical reactions?
- Why is energy released when food molecules change?
- How do new molecules support growth?
- How can we model these processes to explain what happens?
Common Misconceptions
- Atoms are destroyed or lost during digestion or chemical reactions in organisms.
- Energy is created during chemical reactions rather than released from breaking bonds.
- Food molecules simply disappear instead of being rearranged into new molecules.
- Chemical reactions inside organisms do not involve rearranging atoms, only physical changes.
Differentiation
Support and Intervention
Provide sentence starters and visual aids to help students describe chemical reactions. Use physical models or manipulatives to represent atoms and molecules. Offer guided questions to scaffold model building and explanations.
English-Language Learner Support
Use clear visuals and diagrams to support vocabulary understanding. Provide bilingual glossaries for key terms like 'chemical reaction' and 'molecule'. Encourage peer discussion to practice scientific language in context.
Advanced and Extension
Challenge students to include energy flow in their models explicitly. Ask students to research and present on cellular respiration as an example of these chemical reactions. Encourage students to critique and improve their models based on peer feedback and scientific accuracy.
Assessment
- Observe student participation in modeling activities and discussions.
- Check student explanations for understanding of conservation of matter and energy release.
- Use questioning to probe student reasoning during model development.
- Explain in your own words how food molecules change inside an organism and why energy is released.
- Draw a simple model showing atoms being rearranged during digestion.
- Create a detailed model and explanation of how food is chemically rearranged in an organism to support growth and release energy.
- Write a paragraph explaining the conservation of matter during these chemical reactions and how energy flows through the organism.
Answer Guide
- What happens to food molecules during chemical reactions inside an organism?
Answer: Food molecules are broken down and their atoms are rearranged to form new molecules that support growth or release energy. - Why are atoms conserved during these chemical reactions?
Answer: Because atoms are neither created nor destroyed in chemical reactions; they are only rearranged. - How is energy involved in the rearrangement of food molecules?
Answer: Energy is released when chemical bonds in food molecules are broken and can be used by the organism for life processes. - What does a model of food molecule rearrangement inside an organism show?
Answer: It shows food molecules breaking down into smaller parts, atoms being rearranged into new molecules, and energy being released or stored. - Why is it important to understand these chemical reactions in organisms?
Answer: Understanding these reactions explains how organisms grow, get energy, and maintain life by transforming food into useful molecules and energy.
Real-Life Application
Students can discuss with family members how the food they eat provides energy and building materials for their bodies, relating the lesson to everyday life.
Homework or Home Connection
- Students can discuss with family members how the food they eat provides energy and building materials for their bodies, relating the lesson to everyday life.
Lesson Summary
Food molecules inside organisms undergo chemical reactions where they are broken down and rearranged into new molecules that support growth or release energy. Atoms are conserved during these reactions, meaning they are not lost but simply rearranged. Energy released from breaking chemical bonds powers life processes. Developing and using models helps students visualize and explain these important biological processes, fulfilling NGSS standard MS-LS1-7.
Teacher Notes
Use the exact standards alignment and retrieved-source provenance stored with this enrichment.