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 clathrate becomes clear that all the above-mentioned speculations rest on extremely unstable bases. On Enceladus decomposition of carbon dioxide clathrate is a possible way to explain the formation of gas plumes. In Europa (moon), clathrate should be important for storing carbon dioxide. In the conditions of the subsurface ocean in Europa, carbon dioxide clathrate should sink, and therefore not be apparent at the surface. The hydrate structures are stable at different pressure-temperature conditions depending on the guest molecule. Here is given one Mars-related phase diagram of CO hydrate, combined with those of pure CO and water (Genov 2005). CO hydrate has