Plants use light energy to synthesize organic molecules from mineral compounds drawn from the soil or the aquatic environment (water and mineral salts). The ensuring reactions are what is referred to by the term “photosynthesis”. Leaves are the seat of photosynthesis in green plants. An important byproduct of the process is the release of molecular oxygen composed of two oxygen atoms (O₂). Photosynthesis is suspended at night, though the plant “breathes” continuously, day and night. Over a 24-hour period, the plant produces less carbon dioxide by breathing than it does molecular oxygen by photosynthesis during the day.