Photosynthesis Light Reactions
aligned to Honors Biology
Learning Objective
I can describe how light energy is converted into chemical energy during the light reactions of photosynthesis.
Lesson Flow
Watch Video
Photosynthesis (in detail)
Beverly Biology
Guided Notes
Key concepts students will learn:
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In the light-dependent reactions, chlorophyll in photosystem II absorbs sunlight, causing electrons to become excited and flow through the thylakoid membrane.
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As electrons move through the thylakoid membrane, protein pumps pull hydrogen ions into the thylakoid, creating a high concentration, while water molecules are broken down to replenish electrons in photosystem II and release oxygen.
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Sunlight also strikes photosystem I, exciting its electrons, and together with electrons from photosystem II, they power the creation of NADPH, a hydrogen carrier, and the diffusion of hydrogen ions through ATP synthase to produce ATP.
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The light-dependent reactions convert light energy into chemical energy in the form of ATP and NADPH, while also producing oxygen as a byproduct, but no glucose is created at this stage.
Practice
12 questions • Multiple choice & Short answer
Exit Ticket
“Describe how light energy is converted into chemical energy during the light-dependent reactions of photosynthesis. Be sure to mention the roles of chlorophyll, photosystems, and the electron transport chain.”
Teacher Guide
Get the complete package:
- Answer keys for all questions
- Differentiation strategies
- Extension activities
- Printable student handouts
