Here's a breakdown:

* Photo- refers to light.

* Phosphorylation refers to the addition of a phosphate group to a molecule.

During photophosphorylation, light energy is used to energize electrons, which then move through an electron transport chain. This movement of electrons creates a proton gradient across a membrane, and the energy stored in this gradient is used to drive the production of ATP from ADP and inorganic phosphate.

Photophosphorylation is a key part of the light-dependent reactions of photosynthesis, which ultimately produce ATP and NADPH, both of which are necessary for the light-independent reactions (Calvin Cycle) to fix carbon dioxide and produce sugars.