From SM:

A basic starting place:

http://en.wikipedia.org/wiki/Primary_production
http://en.wikipedia.org/wiki/Calvin_cycle
http://en.wikipedia.org/wiki/Light-dependent_reactions

From the last one...

The light-dependent reactions begin in photosystem II. When a chlorophyll a molecule within the reaction center of PSII absorbs a photon, an electron in this molecule attains a higher energy level. Because this state of an electron is very unstable, the electron is transferred from one to another molecule creating a chain of redox reactions, called an electron transport chain...