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C3 Pathway

Macklin Pettee

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What is the C3 Pathway?

  • The C3 pathway is the single step process that takes place in the chloroplast.
  • It is the most common of three metabolic pathways for carbon fixation in photosynthesis, along with C4 and CAM Pathways
  • This process converts carbon dioxide and ribulose bisphosphate (RuBP, a 5-carbon sugar) into two molecules of 3-phosphoglycerate through the following reaction:
    • CO2 + H2O + RuBP → (2) 3-phosphoglycerate
  • C3 plants all create sugars from CO2 through the Calvin cycle
  • Cells involved in the C3 pathway are mesophyll cells

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C3 Plants

  • “Normal plants” - one that doesn't have photosynthetic adaptations to reduce photorespiration
  • About 85% of the plant species on the planet are C3 plants, including rice, wheat, soybeans and all trees.
  • Tend to thrive in areas where sunlight intensity is moderate, temperatures are moderate, carbon dioxide concentrations are around 200 ppm or higher, and groundwater is plentiful.
  • 12 NADPH and 18 ATPs are required to produce glucose
  • Optimum temperature for photosynthesis is 15-25 degrees C

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Works Cited