Give off O 2 as a by-product from the splitting of water. The light reactions power the addition of a phosphate group to ADP in a process called photophosphorylation . First incorporate atmospheric CO 2 into existing organic molecules by a process called carbon fixation , and then reduce fixed carbon to carbohydrate. The process of incorporating CO 2 into organic molecules. ATP provides the chemical energy.
Chloroplasts thus use light energy to make sugar by coordinating the two stages of photosynthesis.
Light reactions occur in the thylakoids of chloroplasts. Calvin cycle reactions occur in the stroma. The Nature of Sunlight Sunlight is electromagnetic energy . The quantum mechanical model of electromagnetic radiation describes light as having a behavior that is both wavelike and particlelike. Wavelike properties of light.