Process of producing energy-rich biomolecules with the help of light energy. Responsible for this are the chloroplasts (organ cells) in which the chlorophyll (leaf green) is found. Through pigments such as chlorophyll, carotenoids and flavonoids in leaves or other green parts of plants, solar radiation is used as an energy source to produce carbohydrate compounds. In the process, carbon dioxide from the air and water are converted to the carbohydrates glucose and fructose, while elemental oxygen is released. Through the absorption of solar energy by plants, around 150 billion tonnes of carbon dioxide are bound and 400 billion tonnes of oxygen are released on Earth every year.