Photosynthesis is a process that turns carbon dioxide into organic compounds , especially sugars using sunlight . Photosynthesis ( foÊ toÊ Ë sÉ nÎ É sÉ s ; from the Greek ( photo - ) , `` light , '' and ( synthesis ) , `` putting together '' , `` composition '' ) is a process that converts carbon dioxide into organic compounds , especially sugars , using the energy from sunlight . Photosynthesis occurs in plants , algae , and many species of bacteria , but not in archaea .