The "Molecule_ReceptorType" concept, defined by the "ChainType" concept of identification, has properties identified in the "StructureType", "Specificity" and "Function" concepts (IDENTIFICATION axiom). The "ChainType" concept is itself defined by the "Molecule_EntityType" and "DomainType" concepts and by concepts of classification (hierarchy). Arrows indicate reciprocal relations "is_defined_by" and "defines", "_has_" and "_for_". These concepts have different levels of granularity, up to six for "Molecule_ReceptorType" and "ChainType".