ATP, NADPH, and hydrogen ions are used to convert PGA (phosphoglycerate) into G3P (glyceraldehyde 3-phosphate) during the Calvin cycle of photosynthesis.

Here's a breakdown:

* PGA is a 3-carbon molecule produced during the initial fixation of carbon dioxide by the enzyme RuBisCo.

* ATP provides the energy needed for the conversion.

* NADPH provides the reducing power (electrons) needed to reduce PGA.

* Hydrogen ions contribute to the overall reduction process.

This conversion is a crucial step in the Calvin cycle, as it leads to the production of G3P, a molecule that can be used to create sugars and other organic molecules.