MS-LS1-6: Photosynthesis and Energy Flow

MS-LS1-6
Photosynthesis and Energy Flow

Middle School

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Learning Objectives

• Explain how photosynthesis helps matter cycle and energy flow in an ecosystem.

• Trace how matter and energy move from the sun to producers and then consumers.

• Describe how plants use the sugar they make for energy, growth, and storage.

• Explain how cellular respiration releases stored energy from food for organisms to use.

Key Vocabulary

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Photosynthesis

The process plants use to convert light energy into chemical energy in the form of food.

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Cycling of Matter

The continuous movement of matter, such as carbon, through an ecosystem’s living and nonliving parts.

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Flow of Energy

The one-way transfer of energy through an ecosystem, starting from the sun to producers and then consumers.

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Producer (Autotroph)

An organism, like a plant, that produces its own food using light, water, and carbon dioxide.

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Consumer (Heterotroph)

An organism that gets energy by eating other organisms because it cannot make its own food.

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Cellular Respiration

The process where cells break down food molecules to release the energy they contain for life functions.

Key Vocabulary

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Organic Molecules

Carbon-based molecules, such as sugars, that are typically made by living organisms like plants.

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Chemical Reaction

A process that involves the rearrangement of atoms in molecules to form entirely new substances.

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Phytoplankton

These are microscopic producers, like algae, that live in aquatic environments and perform photosynthesis.

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Biomass

The total mass of all living or recently living organic matter within a given area.

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How Do Producers Make Food?

Multiple Choice

What is the main purpose of photosynthesis for a producer?

• To capture light energy and convert it into food.

• To absorb nutrients directly from the soil.

• To release carbon dioxide into the atmosphere.

• To break down other organisms for energy.

Multiple Choice

What is the relationship between carbon dioxide (CO₂) and water (H₂O) in the chemical equation for photosynthesis?

• They are the ingredients that get converted into sugar and oxygen.

• They are the forms of energy stored in the cell.

• They are the products released after the process is complete.

• They are the molecules that capture light from the sun.

Multiple Choice

If a healthy plant in sunlight is moved into an environment with no carbon dioxide (CO₂), what is the most likely outcome?

• The plant will be unable to produce the sugar molecules it needs for energy.

• The plant will absorb more water to make up for the lack of CO₂.

• The plant will start producing food using only light energy and oxygen.

• The plant will grow faster because it has less CO₂ to process.

How Plants Use the Food They Make

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Immediate Energy

• Some sugar is used right away for energy needs.

• This process of cellular respiration powers all plant activities.

• This provides the energy for its immediate survival.

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Food Storage

• Excess sugar is stored for the plant to use later.

• It is often stored as starch in roots or leaves.

• This helps plants survive when there is no sunlight.

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Building and Growing

• Sugars are the building blocks for the plant's growth.

• They build biomass like new stems, leaves, and roots.

• This allows the plant to grow bigger and stronger.

Multiple Choice

What is the main purpose of the food that plants make?

• To provide energy for life activities and materials for growth.

• To absorb water and nutrients from the soil.

• To release oxygen into the atmosphere for animals to breathe.

• To create colorful flowers to attract insects.

Multiple Choice

What is the primary benefit of a plant storing excess sugar as starch?

• It allows the plant to have a source of energy when there is no sunlight.

• It helps the plant's leaves absorb more sunlight.

• It makes the plant grow taller to reach the sun.

• It provides the immediate energy needed for cellular respiration.

Multiple Choice

If a healthy plant is moved from a sunny window to a dark closet for a week, what is the most likely way it will survive?

• The plant will use its stored starch to power its life activities.

• The plant will immediately stop all life activities and shut down.

• The plant will grow new leaves to try and find a light source.

• The plant will get the energy it needs directly from the soil.

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Cycling of Matter and Flow of Energy

Energy Flow

• Sunlight provides the energy needed to power the process of photosynthesis in plants.

• Energy flows in one direction, from the sun into the ecosystem, and is not reused.

• This light energy is transformed into chemical energy stored within sugar molecules for the plant.

Matter Cycling

• Matter is taken from the environment as carbon dioxide (CO₂) and water (H₂O).

• Photosynthesis rearranges atoms to create new molecules, such as sugar for energy and oxygen.

• This matter becomes part of the plant and is cycled through the ecosystem continuously.

Multiple Choice

What is the primary difference between how energy and matter move through an ecosystem?

• Energy flows in one direction, while matter is cycled continuously.

• Matter flows in one direction, while energy is cycled continuously.

• Both energy and matter are cycled continuously within the ecosystem.

• Both energy and matter flow in one direction and are not reused.

Multiple Choice

Based on the principles of energy flow and matter cycling, how does photosynthesis function in a plant?

• They convert light energy into chemical energy and use atoms from existing matter to build new molecules.

• They create new energy from sunlight and new matter from carbon dioxide.

• They use chemical energy from the air to rearrange water molecules into sugar.

• They absorb energy from water and matter from sunlight to power photosynthesis.

Multiple Choice

What conclusion is best supported by the information about how energy and matter move through an ecosystem?

• An ecosystem requires a constant external source of energy, but can reuse the same matter over and over.

• Photosynthesis creates all the energy and matter that an ecosystem needs to function.

• Energy and matter are both lost from the ecosystem after a plant uses them.

• The amount of matter in an ecosystem decreases as the amount of energy increases.

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Consumers and Cellular Respiration

Multiple Choice

How do consumers get the energy they need to live?

• By consuming other organisms for food

• By using sunlight to make their own food

• By absorbing nutrients from the soil

• By breathing in carbon dioxide from the air

Multiple Choice

Which statement best describes the role of cellular respiration?

• It is a process that creates food from sunlight.

• It is a process that releases energy from food using oxygen.

• It is a process used only by animals to breathe.

• It is a process that converts carbon dioxide into energy.

Multiple Choice

If a consumer is in an environment with very low oxygen levels, what is the most likely effect on the organism?

• The animal would release more carbon dioxide.

• The amount of energy released from food would decrease.

• The animal would no longer need to eat other organisms.

• The animal would start producing its own oxygen.

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Nutrients For Life

• Food provides energy and the molecular building blocks needed for life's processes.

• Carbohydrates are the main energy source, from simple sugars to complex starches.

• Our bodies can convert food into proteins for building and fats for storage.

• Vitamins and minerals help our cells work correctly but do not provide energy.

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Multiple Choice

What are the two primary things that food provides for the body's life processes?

• Energy and molecular building blocks

• Carbohydrates and simple sugars

• Fats for storage and minerals for cells

• Vitamins and energy for cell function

Multiple Choice

What is the key difference between the function of carbohydrates and the function of vitamins and minerals?

• Carbohydrates are a source of energy, while vitamins and minerals are not.

• Carbohydrates are for building tissues, while vitamins and minerals are for energy.

• Carbohydrates are for energy storage, while vitamins and minerals are building blocks.

• Carbohydrates help cells work correctly, while vitamins and minerals provide energy.

Multiple Choice

A growing teenager is told by a doctor that their body needs more materials to build new muscle. Which nutrient function is most critical to meet this specific need?

• The main energy supply from carbohydrates.

• The conversion of food into proteins for building tissues.

• The storage of energy in the form of fats.

• The role of minerals in helping cells work correctly.

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Common Misconceptions

Misconception	Correction
A plant's mass comes from the soil.	A plant's mass is mainly built from carbon from the air (CO2).
Only animals perform cellular respiration.	Plants also perform cellular respiration to break down sugars for energy.
Energy and matter are the same.	Energy flows through an ecosystem, while matter is cycled within it.

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Summary

• Photosynthesis uses sunlight, carbon dioxide, and water to create sugar and oxygen.

• This process drives the cycling of matter and the flow of energy.

• Plants use the sugar they produce for energy, growth, and storage.

• Consumers get matter and energy by eating plants or other organisms.

• Cellular respiration releases the energy stored in sugar for producers and consumers.

• Photosynthesis and respiration are linked, creating a continuous cycle of matter.

Poll

On a scale of 1-4, how confident are you in explaining how matter cycles and energy flows through an ecosystem, starting from the sun?

• 1

• 2

• 3

• 4