The light reactions convert light energy to chemical energy

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The light reactions convert light energy to
chemical energy

• Concept 8.2

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Light Energy and Pigments

• Wavelengths
• Distance between two adjacent waves
• Electromagnetic Spectrum
• Range of types of electromagnetic energy

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Different wavelengths

• The smaller the wavelength the more energy
• UV light good or bad??

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Pigments and Color

• Three things can happen
• Absorbed
• Transmitted
• Reflected

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Harvesting Light Energy

• Photosystem (mini solar collectors)
• Clusters of chlorophyll (pigments)
• Chlorophyll a and b
• Carotenoids

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Chemical Products of Light Reactions

• Photosystem 1 (water splitting)
• Traps light energy and transfers the light
  excited electrons to the ETC
• ETC (connect P1 and P2) release energy to make
  ATP
• Photosystem 2 (NADPH producing)
• Transfers excited electrons and H to an NADP to
  make NADPH

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The Calvin Cycle makes sugar from CO2

• Concept 8.3

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