Which of the Following Explains Why the Ferrous Ion Is

question 17

Multiple Choice

Which of the following explains why the ferrous ion is not oxidized to the ferric state in the globin proteins even though free heme in solution is readily oxidized?

• A)when bound to globins, the heme is always planar; when free in solution, heme adopts a non-planar configuration which allows the oxidation of the iron
• B)the globin proteins provide a hydrophobic environment that prevents oxidation
• C)coordination with the proximal histidine allows any oxidized iron to be rapidly reduced back to the ferrous state
• D)since the oxygen is hydrogen bound to the distal histidine, if oxidation of iron does occur, the distal histidine allows for rapid reduction
• E)none of the above

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Definitions:

Hydrogen Ion

An atom of hydrogen that has lost its electron, resulting in a positively charged ion, H+.

Hydroxide Ion

A negatively charged ion made of oxygen and hydrogen (OH-), commonly found in bases.

Organic Extraction

A separation process for removing one or more compounds from a mixture using an organic solvent.

Neutral Organic

Organic compounds that are neither acidic nor basic, often characterized by their lack of charged functional groups.