Question

Iron in the diet of animals is predominantly in the ferric form, but it must be reduced to the ferric form by a specific ferrireductase before it can be transported across the cell membrane into the cell: To be absorbed, dietary iron… must be in its ferrous Fe2+form. A ferric reductase enzyme on the enterocytes’ brush border, duodenal cytochrome

B (Dcytb), reduces ferric Fe3+to Fe2+. A protein called divalent
metal transporter 1 (DMT1), which can transport several divalent
metals across the plasma membrane, then transports iron across the enterocyte’s cell membrane into the cell. ( ) Why is this necessary?

Answer 1

Iron in the diet of animals is predominantly in the ferric form, but it must be reduced to the ferrous form before it can be transported across the cell membrane into the cell. This reduction is carried out by the enzyme duodenal cytochrome B (Dcytb) located on the brush border of enterocytes. The iron is then transported across the cell membrane into the cell by a protein called divalent metal transporter 1 (DMT1).

Step-by-step explanation:

In the diet of animals, iron is predominantly in the ferric form (Fe³+), but it must be reduced to the ferrous form (Fe²+) before it can be transported across the cell membrane into the cell. This reduction is carried out by an enzyme called ferrireductase, specifically duodenal cytochrome B (Dcytb), located on the brush border of enterocytes. Dcytb converts ferric Fe³+ to ferrous Fe²+ form. The reason this reduction is necessary is that the divalent metal transporter 1 (DMT1), which transports iron across the cell membrane, can only recognize and transport ferrous Fe²+ form of iron.

Iron in its ferric Fe³+ form is not easily soluble and therefore cannot be efficiently absorbed by the body. However, once iron is reduced to the ferrous Fe²+ form, it becomes more soluble and can easily pass through the cell membrane via DMT1. This allows the iron to be absorbed by the enterocyte and ultimately be transported into the bloodstream for use in various biological processes.