Recognize the key steps in the Calvin cycle: The Calvin cycle consists of three main phases: (1) Carbon fixation, where CO₂ is attached to ribulose-1,5-bisphosphate (RuBP) by the enzyme RuBisCO; (2) Reduction, where ATP and NADPH are used to convert 3-phosphoglycerate into G3P; and (3) Regeneration, where RuBP is regenerated to continue the cycle.