This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water â hence the name photosynthesis, from the Greek Ïá¿¶Ï, phÅs, light, and ÏÏÎ½Î¸ÎµÏÎ¹Ï, synthesis, putting together.arbon dioxide is converted into sugars in a process called carbon fixation. Carbon fixation is an endothermic redox reaction, so photosynthesis needs to supply both a source of energy to drive this process, and the electrons needed to convert carbon dioxide into a carbohydrate.