Both the light dependant and light independent reactions are important steps in photosynthesis and require light to proceed. The major differences between these two reactions are where the reactions take place and what each reaction absorbs. The light reaction occurs in the grana and converts the light energy into a chemical energy in from of ATP and NADPH. By splitting a water molecule, the light reaction releases oxygen. The dark reaction takes place in the stroma and functions in changing CO2 into glucose from ATP and NADPH. The carbon fixation occurs by utilizing the ATP and NADPH that were produced in the light reactions earlier.