electron transport chain of the mitochondrian

The electron transport chain in the mitochondria is a group of four large multiprotein complexes that span the inner mitochondrial membrane. As the name implies its function is to transport electrons from either NADH or FADH2 to their final repository which is water molecules. Thus water is synthesized during oxidative mitochondrial function.

The electron transport chain includes four large multiprotein complexs:

• NADH-CoQ reductase complex

• Succinate-CoQ reductase complex

• CoQh2-cyt c reductase complex

• Cyt c oxidase complex

The diagram below illustrates the direction of electron transport within the electron transport chain

The electron transport chain is also a series of coupled oxidation-reduction reactions.

As one substance is enzymatically oxidized another becomes enzymatically reduced. This process continues until the electrons are found in their final reposity with is water.

The above diagram illustrates the path of electron flow (in red) in the electron transport chain

Also several important features of the electron transport chain are implied:

• each of the reactions is exergonic and thus releases free energy. This free energy is used to translocate protons across the inner mitochondrial membrane.

• the electrons that finally ends up in water are of low energy.

• during the coupled oxidation reduction reactions iron ions that are complexed with the proteins become oxidized and reduced. That is, the Fe ions participate in catalysis.