Here's a breakdown:

* Light energy is absorbed by chlorophyll and other pigments in the chloroplasts.

* This energy is used to excite electrons, which move through an electron transport chain.

* This electron flow powers the creation of a proton gradient across the thylakoid membrane.

* The proton gradient is then used by ATP synthase to produce ATP (adenosine triphosphate), a molecule that stores chemical energy.

* The excited electrons also reduce NADP+ to NADPH, another energy-carrying molecule.

So, the light reactions essentially capture light energy and convert it into forms of chemical energy that can be used in the Calvin cycle (dark reactions) to synthesize glucose.