Light independent stage

    Cards (6)

    • Light-independent stage of photosynthesis
      Also known as the Calvin cycle
    • Light-independent stage
      • Produces complex organic molecules, including carbohydrates such as starch, sucrose, and cellulose
      • Does not require energy from light and can take place in light or darkness
      • Requires inputs of ATP and reduced NADP from the light-dependent stage
    • Calvin cycle
      1. Rubisco catalyses the fixation of carbon dioxide by combination with ribulose bisphosphate (RuBP)
      2. GP is reduced to triose phosphate (TP) in a reaction involving reduced NADP and ATP
      3. RuBP is regenerated from TP in reactions that use ATP
    • Carbon fixation
      • Carbon dioxide combines with ribulose bisphosphate (RuBP)
      • Rubisco (ribulose bisphosphate carboxylase) catalyses this reaction
      • The resulting six-carbon (6C) compound is unstable and splits into two molecules of glycerate 3-phosphate (GP)
    • Reduction of glycerate 3-phosphate
      1. Energy from ATP and hydrogen from reduced NADP are used to reduce glycerate 3-phosphate (GP) to triose phosphate (TP)
      2. One-sixth of the TP molecules are used to produce useful organic molecules needed by the plant
    • Regeneration of ribulose bisphosphate
      1. Five-sixths of the triose phosphate (TP) molecules are used to regenerate ribulose bisphosphate (RuBP)
      2. This process requires ATP
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