* The goal: The Calvin cycle's ultimate goal is to use energy from ATP and reducing power from NADPH (both generated in the light-dependent reactions of photosynthesis) to convert carbon dioxide into sugar.
* Carbon fixation: The cycle begins with the enzyme RuBisCO, which fixes carbon dioxide onto a five-carbon molecule called ribulose-1,5-bisphosphate (RuBP). This creates a six-carbon molecule that quickly breaks down into two 3-carbon molecules called 3-phosphoglycerate (3-PGA).
* Reduction: 3-PGA is then reduced to G3P using ATP and NADPH.
* Regeneration: Most of the G3P is used to regenerate RuBP to continue the cycle, but a small portion is used to produce glucose and other organic molecules.
Therefore, G3P is the primary product of the Calvin cycle, and it represents the "sugar" produced by photosynthesis.
