This ontology is intended as an incomplete representation of molecules. It is for tutoring purpose. It is heavily inspired from ChEBI (http://www.ebi.ac.uk/chebi/). As usual, the good stuff comes from them; the errors and over-simplifications are ours. 1.0 2 Helium HCl Cations are positively charged ions, formed when an atom loses electrons in a reaction. Catabolism is the set of metabolic pathways which break down molecules into smaller units and release energy. In catabolism, large molecules such as polysaccharides, lipids, nucleic acids and proteins are broken down into smaller units such as monosaccharides, fatty acids, nucleotides and amino acids, respectively. Phosphorus A chemical element is a type of atom that is distinguished by its atomic number; that is, by the number of protons in its nucleus 4 Fluoride 1 Hydrogen Phosphide Neon Oxygen Anions are negatively charged ions, formed when an atom gains electrons in a reaction. Nitrogen An ion is an atom or molecule which has lost or gained one or more valence electrons, giving it a positive or negative electrical charge. An ion is a molecular structure having a net electric charge CH4 Magnesium 3 NaOH Fluorine A molecule is a sufficiently stable electrically neutral group of at least two atoms in a definite arrangement held together by very strong chemical bonds . It can also be defined as a unit of two or more atoms held together by covalent bonds. A molecule is an electrically neutral entity consisting of more than one atom. 2 Anabolism is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy. One way of categorizing metabolic processes, whether at the cellular, organ or organism level is as 'anabolic' or as 'catabolic', which is the opposite. Sodium Argon H2O Sulfide Carbon C6h12O6 Lithium Sulfur Oxide Beryllium Chloride H+ Silicon Chlorine Aluminium Nitride Boron C24H24N4O4 NaCl