While the Calvin cycle uses 6 molecules of CO2 to produce one molecule of glucose, it actually produces two molecules of G3P. One of these molecules is used to regenerate the starting molecule, RuBP, and the other is available to be used by the plant for other processes.

Here's a breakdown:

* Calvin Cycle: The Calvin cycle is a series of biochemical reactions that use carbon dioxide and ATP (energy) to produce G3P.

* G3P: A three-carbon sugar that is a key intermediate in many metabolic pathways.

* Glucose: Glucose is a six-carbon sugar that is produced from two molecules of G3P.

So, while glucose is the ultimate product we often think of in relation to photosynthesis, G3P is the direct, primary product of the Calvin cycle.