During the first stage of photosynthesis, called the light-dependent reactions, plants produce ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate).

Here's a breakdown:

* ATP is the energy currency of cells. It's used to power other metabolic processes, including the second stage of photosynthesis.

* NADPH is an electron carrier that carries high-energy electrons to the second stage of photosynthesis.

These molecules are essential for the second stage (the Calvin cycle), where carbon dioxide is converted into sugar.