The chemical reactions and pathways involving any member of a large group of derivatives or analogs of porphyrin. Porphyrins consists of a ring of four pyrrole nuclei linked each to the next at their alpha positions through a methine group [goid 6778] [evidence IEA]; The regulation of the levels, transport, and metabolism of iron ions within a cell or between a cell and its external environment [goid 6879] [evidence IEA]; The chemical reactions and pathways resulting in the formation of substances; typically the energy-requiring part of metabolism in which simpler substances are transformed into more complex ones [goid 9058] [evidence IEA]; The chemical reactions and pathways leading to the formation of tetrapyrroles, natural pigments containing four pyrrole rings joined by one-carbon units linking position 2 of one pyrrole ring to position 5 of the next [goid 33014] [evidence IEA]; The chemical reactions and pathways involving any member of a large group of derivatives or analogs of porphyrin. Porphyrins consists of a ring of four pyrrole nuclei linked each to the next at their alpha positions through a methine group [goid 6778] [evidence IEA]; The regulation of the levels, transport, and metabolism of iron ions within a cell or between a cell and its external environment [goid 6879] [evidence IEA]; The chemical reactions and pathways resulting in the formation of substances; typically the energy-requiring part of metabolism in which simpler substances are transformed into more complex ones [goid 9058] [evidence IEA]; The chemical reactions and pathways leading to the formation of tetrapyrroles, natural pigments containing four pyrrole rings joined by one-carbon units linking position 2 of one pyrrole ring to position 5 of the next [goid 33014] [evidence IEA]; A change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a stimulus indicating lowered oxygen tension. Hypoxia, defined as a decline in O2 levels below normoxic levels of 20.8 - 20.95%, results in metabolic adaptation at both the cellular and organismal level [goid 1666] [pmid 16234850] [evidence IDA]; The chemical reactions and pathways involving any member of a large group of derivatives or analogs of porphyrin. Porphyrins consists of a ring of four pyrrole nuclei linked each to the next at their alpha positions through a methine group [goid 6778] [evidence IEA]; The chemical reactions and pathways resulting in the formation of heme, any compound of iron complexed in a porphyrin (tetrapyrrole) ring, from less complex precursors [goid 6783] [evidence ISS]; The chemical reactions and pathways resulting in the formation of heme, any compound of iron complexed in a porphyrin (tetrapyrrole) ring, from less complex precursors [goid 6783] [pmid 14643893] [evidence NAS]; The chemical reactions and pathways resulting in the formation of substances; typically the energy-requiring part of metabolism in which simpler substances are transformed into more complex ones [goid 9058] [evidence IEA]; The process by which a myeloid precursor cell acquires specializes features of an erythrocyte [goid 30218] [pmid 2050125] [evidence NAS]; The process by which a myeloid precursor cell acquires specializes features of an erythrocyte [goid 30218] [evidence ISS]; A homeostatic process involved in the maintenance of an internal equilibrium of oxygen within an organism or cell [goid 32364] [pmid 16234850] [evidence NAS]; The chemical reactions and pathways leading to the formation of tetrapyrroles, natural pigments containing four pyrrole rings joined by one-carbon units linking position 2 of one pyrrole ring to position 5 of the next [goid 33014] [evidence IEA]; The chemical reactions and pathways resulting in the formation of hemoglobin, an oxygen carrying, conjugated protein containing four heme groups and globin [goid 42541] [evidence ISS]