iron

Examples of iron in the following topics:

• The Iron Cycle

  • Iron (Fe) follows a geochemical cycle like many other nutrients.
  • The Terrestrial Iron Cycle: In terrestrial ecosystems, plants first absorb iron through their roots from the soil.
  • Iron is required to produce chlorophyl, and plants require sufficient iron to perform photosynthesis.
  • Animals acquire iron when they consume plants, and iron is utilized by vertebrates in hemoglobin, the oxygen-binding protein found in red blood cells.
  • The Marine Iron Cycle: The oceanic iron cycle is similar to the terrestrial iron cycle, except that the primary producers that absorb iron are typically phytoplankton or cyanobacteria.

• Changes to Iron Production

• The Iron Curtain

• Iron

  • Fresh iron surfaces appear lustrous silvery-gray but oxidize in normal air to give iron oxides, also known as rust.
  • Unlike many other metals which form passivating oxide layers, iron oxides occupy more volume than iron metal.
  • The iron compounds produced on the largest scale in industry are iron(II) sulfate (FeSO4·7H2O) and iron(III) chloride (FeCl3).
  • Iron(II) compounds tend to be oxidized to iron(III) compounds in the air.
  • Iron reacts with oxygen in the air to form various oxide and hydroxide compounds; the most common are iron(II,III) oxide (Fe3O4) and iron (III) oxide (Fe2O3).

• Iron Oxidation

  • Ferric iron is an anaerobic terminal electron acceptor, with the final enzyme a ferric iron reductase.
  • Since some ferric iron-reducing bacteria (e.g.
  • Ferrous iron is a soluble form of iron that is stable at extremely low pHs or under anaerobic conditions.
  • There are three distinct types of ferrous iron-oxidizing microbes.
  • Outline the purpose of iron oxidation and the three types of ferrous iron-oxidizing microbes (acidophiles, microaerophiles and anaerobic photosynthetic bacteria)

• Iron Overload and Tissue Damage

  • Iron overload, also known as hemochromatosis, is an accumulation of iron in the body and can lead to tissue and organ damage.
  • Thus, many methods of iron storage have developed.
  • In medicine, iron overload indicates accumulation of iron in the body from any cause.
  • Once iron and other markers are within the normal range, phlebotomies may be scheduled every other month or every three months depending upon the patient's rate of iron loading.
  • Discuss the causes of iron overload and the resulting tissue damage

• Siderophores

  • Siderophores produce specific proteins and some siderophores form soluble iron complexes to aid in iron acquisition for survival.
  • The siderophores are then utilized by the pathogen to obtain iron.
  • Therefore, siderophores are chelating agents that bind the iron ions.
  • In iron deficient environments, the siderophores are released and allow for the formation of water soluble-Fe3+ complexes to increase iron acquisition.
  • The iron will then be utilized in numerous cellular processes.

• Iron-Binding Proteins

  • Iron-binding proteins are proteins generally used to play roles in metabolism.
  • Iron-binding proteins are serum proteins, found in the blood, and as their name suggests, are used to bind and transport iron.
  • Transferrins are iron-binding blood plasma glycoproteins that control the level of free iron in biological fluids .
  • Transferrin glycoproteins bind iron very tightly, but reversibly.
  • Although iron bound to transferrin is less than 0.1% (4 mg) of the total body iron, it is the most important iron pool, with the highest rate of turnover (25 mg/24 h).

• Cast-Iron Architecture

  • Cast-iron architecture was a prominent style in the Industrial Revolution era when cast iron was relatively cheap, and modern steel had not yet been developed.
  • In the 1850s the cheapness and availability of cast iron led James Bogardus of New York City to advocate and design buildings using cast iron components.
  • Cast iron has some architectural advantages, as well as some serious weaknesses.
  • Cast iron was also used widely in bridge construction for the new railway system, sometimes with horrific results, especially when cast iron girders were used instead of arches.
  • The weakest parts of the bridge were cast iron lugs holding tie bars in place, and cast iron in new bridges was effectively abandoned after the disaster.

• Siderophores

  • However, iron is not always readily available; therefore, microorganisms use various iron uptake systems to secure sufficient supplies from their surroundings.
  • There is considerable variation in the range of iron transporters and iron sources utilized by different microbial species.
  • Pathogens, in particular, require efficient iron acquisition mechanisms to enable them to compete successfully for iron in the highly iron-restricted environment of the host's tissues and body fluids.
  • For example, the anthrax pathogen Bacillus anthracis releases two siderophores, bacillibactin and petrobactin, to scavenge ferric iron from iron proteins.
  • Siderophores are usually classified by the ligands used to chelate the ferric iron.