Light independent

• Calvin cycle takes place in stroma
• RuBP is regenerated by ATP, NADPH and CO2
• ATP is used to convert RuBP into two molecules of 3-phosphoglycerate (3PG)
• 1. An enzyme called rubisco (ribulose bisphosphate carboxylase) is used to combine CO2 with a molecule called ribulose bisphosphate (RuBP) to form 2 molecules of glycerate phosphate (GP)
  2. 2xGP is converted to three molecules of TP using the energy from the breakdown of 2ATP to ADP and2NADPH to NADP
  3. Some TP is converted to glucose. The rest is used to regenerate RuBP using the energy from the breakdown of 1 ATP to ADP

  The ATP and NADPH used in the Calvin Cycle come from the light-dependent reaction
• 1. CO, reacts with RuBP (ribulose bisphosphate)

  (5C), catalysed by the enzyme rubisco.

  2. Produces 2 molecules of glycerate 3-phosphate

  (GP) (3C).

  3. GP reduced to triose phosphate (TP) using products from light dependent reaction:

  energy from the

  hydrolysis of ATP and H+ from reduced NADP.

  4. Some TP converted into useful organic substances eg. glucose.

  5.(5/6) TP used to regenerate RuBP (using rest of ATP).

  
• Cycle has to occur 6x for useful organic substances to be produced