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Chemistry LibreTexts

Digging Deeper: Light-Dependent Reactions

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  • On the last page you were introduced to the basics of the light-dependent reactions in photosynthesis. Let's take a little closer look at this process to begin with. 

    The main function of the light-dependent reactions are to capture and transfer energy. The light reactions can be further broken down into Photosystem II and Photosystem I. 

    Photosystem II

    1. Energy absorbed
    2. Water molecules are broken down
    3. Hydrogen ions are transported

    Photosystem I

    1. Energy is absorbed
    2. NADPH is produced when electrons are added to NADP
    3. Hydrogen ions diffuse through a protein channel in the thylakoid membrane
    4. ADP is changed to ATP when hydrogen ions flow through the protein channel


    Go to the WyzAnt Photosynthesis lesson, read two pages, Photosynthesis and Light and Dark Reactions

    In addition watch these two animations to help you understand this complicated process of photosynthesis. 

    1. Photosynthesis
    2. Electron Transport Chains