Answer is: light-dependent reactions and light-independent reactions (dark or carbon reactions or Calvin cycle).
In photosynthesis (convert light energy into chemical energy),
the carbon in carbon(IV) oxide is being reduced to form glucose.
The pigment chlorophyll absorbs one photon and loses one electron (it passed throw an electron transport chain) in the light-dependent reactions.
The enzyme RuBisCO takes carbon(IV) oxide in the light-independent reactions.
