Q: How are the first stage and the second stage of photosynthesis connected to each other?

Flexi Says: Photosynthesis is a series of chemical reactions divided into two stages, the light reactions and the Calvin cycle. ATP and NADPH are generated by two electron transport chains during the light reactions. The Calvin cycle uses CO₂ and the energy temporarily stored in ATP and NADPH to make the sugar glucose.

Learn more in the Photosynthesis and Calvin Cycle lessons.