Light-independent stage

    Cards (9)

    • All occurs in the stroma
    • Calvin cycle
      A) CO2
      B) RuBisCO
      C) RuBP
      D) Unstable intermediate
      E) GP
      F) GP
      G) ATP
      H) Reduced NADP
      I) TP
      J) TP
    • 3 stages of the Calvin cycle:
      1. Fixation
      2. Reduction
      3. Regeneration
    • 1st step of the Calvin cycle - Fixation:
      1. CO2 diffuses into intracellular spaces in the within the spongy mesophyll
      2. Combines with 5C RuBP - Carbon is fixed being incorporated into an inorganic molecules
      3. Catalysed by RuBisCO
      4. 6C Unstable intermediate produced
      5. Broken down to 2 3C GP molecule
    • 2nd step of the Calvin cycle - Reduction:
      1. Each GP converted to 2 3C TP molecules
      2. The TP molecules are reduced by NADPH and energy is provided via ATP
    • 3rd step of the Calvin cycle - Regeneration:
      1. Majority of TP produced is recycled to regenerate RuBP
      2. Some TP molecules are the starting point for biological molecules such as carbohydrates, lipids and proteins
    • RuBisCO:
      • Enzymes that catalyses the combination of CO2 and RuBP
      • Very inefficient - competitively inhibited by oxygen - ALOT needed to carry out photosynthesis
      • Probably most abundant enzyme in the world
    • For 1 glucose molecule to be produced:
      1. 6 CO2 molecules have to enter the Calvin cycle - 6 full turns
      2. 12 TP molecules produced - 2 removed to form 1 glucose
      3. 10 TP recycled to regenerate 6 RuBP
    • 10 x 3C TP = 30C shuffled giving 6 x 5C RuBP = 30C
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