Why does photosynthesis occur in plants?
Photosynthesis occurs in order to create sugars and oxygen from water and carbon dioxide. The splitting of water into its constituent atoms is unique in the biological world. It is able to occur because of the existence of chlorophylls (chlorophyll a and b) and associated pigments (mainly carotenoids) which are able to absorb light of the correct wavelengths from the sun. It is the radiation from the sun which provides the energy to split water. Once the hydrogen and oxygen are separated they can react with the carbon from carbon dioxide to form simple sugars which are then processed into more complex molecules. Photosynthesis converts inorganic elements into organic molecules. When eaten by herbivores, the energy stored in plants is released; this energy is then passed up the food chain. Thus, photosynthesis powers the whole of the living world.
