"Some bacteria produce hair-like filaments that act as wires, ferrying electrons back and forth between the cells and their environment."
This is fascinating.
"The discovery of electric bacteria shows that some very basic forms of life can do away with sugary middlemen and handle the energy in its purest form – electrons, harvested from the surface of minerals. "It is truly foreign, you know," says Nealson. "In a sense, alien.""
Nice. See the article here for the juicy science details.