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Prof. Oded Béjà (left) and PhD student Ariel Chazan Photo Credit: Technion-Israel Institute of Technology |
Plants convert light into a form of energy that they can use – a molecule called adenosine triphosphate (ATP) – through photosynthesis. This is a complex process that also produces sugar, which the plant can use for energy later, and oxygen. Some bacteria that live in the light-exposed layers of water sources can also convert light to ATP, but the process they use is simpler and less efficient than photosynthesis. Nonetheless, Technion – Israel Institute of Technology researchers now find this process isn’t as straightforward and limited as was previously thought.
Rhodopsin are the light-driven proton pumps that bacteria employ to produce ATP. Whereas photosynthesis is a process that involves multiple stages and proteins, rhodopsin performs everything itself. It is not more efficient, but rather it is like the difference between a medieval workshop and a modern factory. The rhodopsin's are activated by a molecule called “retinal,” which absorbs light. Specifically, in these proteins retinal absorbs green light. A different molecule, a carotenoid “antenna,” can enable it to also absorb blue light as well, increasing the amount of energy the rhodopsin can produce.