Light independent stage

• The light independent stage is called the calvin cycle
• the light independent reaction happens in the Stroma, it is a series of reduction reactions
• the calvin cycle continues until the NADPH, ATP or CO2 is used up.
• the molecules involved:

  Ribulose bisphosphate (5C)

  carbon dioxide (1C)

  glycerate 3 phosphate (3C)

  triose phosphate (3C)
• enzyme = RuBisCo
• aim of the light independent stage is to reduce CO2 to glucose
• the substances needed for the Light independent stage:

  • NADPH , ATP, CO2 , Ribulose Bisphosphate (RuBP), RuBisCo

  The substances produced:

  • NADP , ADP , Pi, glucose
• Carbon dioxide (1C) is added to ribulose bisphosphate (5C) catalysed by the enzyme RuBisCo.

  A highly unstable 6C molecule is produced which immediately splits into two glycerate-3-phosphate (3C)
• the two glycerate-3-phosphate molecules are reduced to produce two triose phosphate molecules.

  to allow this reduction reaction NADPH is oxidised and ATP is hydrolysed
• the two triose phosphate molecules are used to make glucose and resynthesise Ribulose bisphosphate. the resynthesis of Ribulose bisphosphate requires the hydrolysis of ATP.
• five out of six turns of the Calvin cycle resynthesise Ribulose bisphosphate.

  one out of six turns of the Calvin cycle form glucose
• Glycerate-3-phosphate can be written as (GP)

  triose phosphate can be written as (TP)

  ribulose bisphosphate can be written as (RuBP)