* 3 ATP

* 2 NADPH

Let's break it down:

* The Calvin Cycle: This is the series of reactions in photosynthesis where CO2 is converted into sugar.

* CO2 fixation: The first step of the Calvin cycle involves the enzyme rubisco, which adds CO2 to a 5-carbon sugar called RuBP (ribulose bisphosphate). This creates an unstable 6-carbon molecule that quickly splits into two 3-carbon molecules (3-PGA).

* Reduction: This phase involves converting 3-PGA into glyceraldehyde 3-phosphate (G3P), a sugar that can be used to make glucose. This step requires 1 NADPH and 1 ATP per 3-PGA molecule. Since we have two 3-PGA molecules, we need 2 NADPH and 2 ATP.

* Regeneration: The final step involves regenerating RuBP, which is needed to continue the cycle. This step requires 1 ATP per molecule of RuBP. Since we need to regenerate one molecule of RuBP for every CO2 fixed, we need an additional 1 ATP.

In total, we need 3 ATP and 2 NADPH to fix one CO2 molecule.