The process of photosynthesis fuels life on Earth. Its first step is capturing the energy in sunlight. Light-capturing proteins in photosynthetic organisms are often seen closely crowded together in the cellular membrane, forming hundred nanometer-sized patches. Such "photosynthetic membranes" can be flat or spherical, depending on bacterial species (see the October 2007 highlight on Life's Solar Battery, the August 2010 highlight on Bacterial Solar Energy Engineering, and a recent review); in case of a certain mutant bacterium the membrane forms the cylindrical surface of a rod. This membrane is actually an ideal case for scientific investigation, since it contains only one type of protein complex organized in an orderly fashion, such that placement of all proteins is known with atomic precision. As reported recently, researchers have used the cylindrical photosynthetic membrane as a model system to elucidate in great detail how light is captured, and how the light energy is passed around the light-capturing proteins until it is utilized to charge the membrane through electron transfer. The theory of these quantum mechanical processes has been described before (see the April 2010 highlight on Light Capture). More information can be found on our photosynthetic core complex website.