1. Bellwork What are the three most critical substances plants need to survive?

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Photosynthesis
Image sources:
Protista
Plants
Bacteria
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3. Learning Goal
The student will be able to explain how living systems follow the Laws of Conservation of Mass and Energy.

4. What is photosynthesis?
Photosynthesis is a process in some living organisms (plants & bacteria) that uses energy from the sun, carbon dioxide, and water to make sugars (glucose).
Oxygen is released into the air during photosynthesis.
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5. Where does photosynthesis occur?
Photosynthesis takes place in organelles called chloroplasts.
A green pigment called chlorophyll, in chloroplasts, captures energy from sunlight.
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6. What is photosynthesis’s chemical reaction?
6CO2 + 6H2O + Light energy → C6H12O6 + 6O2
Carbon Dioxide + Water + Light energy Glucose + Oxygen
Energy (from sunlight) combines with carbon dioxide and water to form the sugar, glucose, and oxygen gas.
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The teacher should explain that photosynthesis is a chemical process, with reactants and products. (See next slide for details on reactants and products)
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7. 6CO2 + 6H2O + Light energy → C6H12O6 + 6O2
Reactants vs. Products
Reactants are what is needed to make something. The reactants for photosynthesis are: Carbon Dioxide, Water, and Sunlight
6CO2 + 6H2O + Light energy → C6H12O6 + 6O2
Products are what is made. The products for photosynthesis are: Glucose (sugar) and Oxygen
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Reactants vs. Products
Glucose stores chemical energy, and photosynthetic organisms (plants, protists, and bacteria) store glucose.
When another organism, like an animal, eats a photosynthetic organism, they use the stored glucose for energy.
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Teacher notes: Teacher may want to introduce the concept that not all of the glucose produced is stored. Some of the glucose is used for growth, maintained and repair of the plant. (producing flowers, seeds, leaves, growing stem, etc.)
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