Editing Iron oxide (section)

===In nature ===
Iron is stored in many organisms in the form of [[ferritin]], which is a ferrous oxide encased in a solubilizing protein sheath.<ref>{{cite journal|doi=10.1021/cr5004908|title=Unity in the Biochemistry of the Iron-Storage Proteins Ferritin and Bacterioferritin |year=2015 |last1=Honarmand Ebrahimi |first1=Kourosh |last2=Hagedoorn |first2=Peter-Leon |last3=Hagen |first3=Wilfred R. |journal=Chemical Reviews |volume=115 |issue=1 |pages=295–326 |pmid=25418839 |doi-access=free }}</ref>

Species of [[Dissimilatory metal-reducing bacteria|bacteria]], including ''[[Shewanella oneidensis]]'', ''[[Geobacter sulfurreducens]]'' and ''[[Geobacter metallireducens]]'', use iron oxides as [[Electron acceptor|terminal electron acceptors]].<ref>{{cite journal|last1=Bretschger|first1=O.|last2=Obraztsova|first2=A.|last3=Sturm|first3=C. A.|last4=Chang|first4=I. S.|last5=Gorby|first5=Y. A.|last6=Reed|first6=S. B.|last7=Culley|first7=D. E.|last8=Reardon|first8=C. L.|last9=Barua|first9=S.|last10=Romine|first10=M. F.|last11=Zhou|first11=J.|last12=Beliaev|first12=A. S.|last13=Bouhenni|first13=R.|last14=Saffarini|first14=D.|last15=Mansfeld|first15=F.|last16=Kim|first16=B.-H.|last17=Fredrickson|first17=J. K.|last18=Nealson|first18=K. H.|title=Current Production and Metal Oxide Reduction by Shewanella oneidensis MR-1 Wild Type and Mutants|journal=Applied and Environmental Microbiology|date=20 July 2007|volume=73|issue=21|pages=7003–7012|doi=10.1128/AEM.01087-07|pmid=17644630|pmc=2223255|bibcode=2007ApEnM..73.7003B }}</ref>