Fix carbon to produce sugars for growth & metabolism
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What are the 3 stages of the Calvin-Benson cycle?
1) Carbon fixation (CO2 reacted with 5C molecule), 2) Reduction phase (Series of reactions producing 2 3C sugar phosphates), 3) Regeneration of RuBP (5C molecule regenerated and the cycle starts again)
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What is RuBisCo?
Ribulose-1,5-bisphosphate carboxylase oxygenase, large protein complex with 8 large subunits & 8 small subunits, very slow and inefficient so plants make lots in order to compensate
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Describe carbon fixation (Stage 1)
Ribulose-1,5-bisphosphate (RuBP) reacted with 1 molecule of CO2, (Enzyme: RuBisCo), product: 2 3-phosphoglycerate molecules
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What are the 3 stages for fixing carbon through RuBisCo?
1) Enolisation (rearrangement step, double bond in chain) 2) Carboxylation (CO2 reacted to 6C molecule) 3) Cleavage (2 3-PGA molecules produced)
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What is the first step of the reduction phase? (Stage 2)
Uses ATP from light dependent reactions, (Enzyme: Phosphoglycerate kinase), product: 1,3-Bisphosphate
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What is the second step of the reduction phase? (Stage 2)
Describe the first step of regeneration of RuBP (Stage 3)
The 2 3-phosphoglycerate molecules from carbon fixation are catalysed, ATP from light dependent reactions used, (Enzyme: Phosphoglycerate kinase), product: 2 1,3 bisphosphoglycerate molecules
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Describe the second step of regeneration of RuBP (Stage 3)
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