Why Do Plants & Animals Need Iron?

Iron is the 26th element of the periodic table. While iron is best known for its strength and durability, it's also important in biology. Nearly all known forms of life require iron -- including plants and animals.

Features

• Like many transition metals, iron can exist in multiple oxidation states, which basically means that it can form compounds where it has "lost" or "gained" a different number of electrons. Depending on what other atoms are bound to it, iron can also have varying redox potentials, where the redox potential is a measure of how readily it gives electrons to other atoms. These features make iron a useful component of many biological systems.

Function

• Iron is used primarily as an enzyme cofactor, meaning an atom that binds to an enzyme to help it accomplish its task. About two-thirds of the iron in your body is found bound to a protein in your red blood cells called hemoglobin, where it serves to help bind and transport oxygen.

Effects

• Some of iron's most important biological roles are in metabolic processes like cellular respiration. All plants and animals have mitochondria in their cells that help produce the chemical energy the cells need to survive; mitochondria contain cytochrome proteins that play a key role in these processes. Cytochrome proteins have iron atoms bound in a structure called a porphyrin ring; since cytochrome proteins need iron to perform their function, plants and animals cannot survive without iron. Iron is also an important cofactor for many other enzymes that perform essential functions.