Metabolism Autotrophs such as plants can construct the complex organic molecules in cells such as polysaccharides and proteins from simple molecules like carbon dioxide and water. Heterotrophs, on the other hand, require a source of more complex substances, such as monosaccharides and amino acids, to produce these complex molecules. Organisms can be further classified by ultimate source of their energy: photoautotrophs and photoheterotrophs obtain energy from light, whereas chemoautotrophs and chemoheterotrophs obtain energy from inorganic oxidation reactions. Photosynthesis is the synthesis of carbohydrates from sunlight and carbon dioxide (CO). In plants, cyanobacteria and algae, oxygenic photosynthesis splits water, with oxygen produced
Carbon dioxide cleaning In addition, care must be taken to prevent the concentration of carbon dioxide in the work area from exceeding safe levels. Some commercial grades of carbon dioxide may contain traces of heavy hydrocarbons, which can be left behind on the surface being cleaned. Abrasive particles originating in the cleaning equipment itself may need to be filtered out as well. The low temperature of the carbon dioxide stream can also induce moisture condensation on the part, which may be mitigated with hot plates, heat guns, heat lamps, or dry boxes. Ionization caused by the flowing gas can result in potentially damaging