And what the electron transport chain does is it basically transports electrons all the way to the final electron acceptor known as oxygen and we form water as a result. And this electron transport chain also establishes an electrochemical gradient that is used to synthesize ATP molecules. And it's the ATP molecule that is used by the cell as our energy source. So let's take a look at the structure of our electron transport chain. So the electron transport chain is shown in the following diagram. So we have the inner membrane of the mitochondria, which is a phospholipid bilayer.