1: Carbon FixationThe enzyme rubisco combines CO2 with 5-carbon sugar rubulose biphosphate (RuBP). The unstable product formed splits into 2 molecules of 3-carbon 3-phosphoglyceric acid (3-PGA).Step 2: ReductionEnergy from 6 molecules of ATP is used to oxidize NADPH to NADP+. Six molecules of 3-PGA are reduced, producing six molecules of energy-rich 3-carbon sugar G3P.Step 3: Release of one molecule of G3PFive of the previously created G3Ps remain in the cycle, but one molecule is released.AdvertisementUpgrade to remove adsStep 4: Regeneration of RuBPA series of chemical reactions uses energy from ATP to rearrange the atoms of the 5 G3P molecules, (15 total carbons), which forms 3 RuBP molecules (15 total carbons).
These will start another turn of the cycle.Produced by Step 1Six molecules of 3 Carbon 3-PGAProduced by Step 2Six molecules of 3 Carbon G3PResult of Step 3One G3P is released and five continue in the cycleProduced by Step 4Three molecules of 5 Carbon RuBP