Quantum Biology Reviews
Clearly, the laws of physics hold and are exploited in living organisms. Speaking as a physicist, most biological characteristics stem from the laws of classical physics that students learn in their first year. However, crucial characteristics in organisms are governed by quantum physics, a higher and still active area of physics. The latter characteristics are those in which biological processes involve the jumps of electrons from one state to another state: electrons are exemplary quantum particles. The quantum behavior of electrons cover all chemical transformations, for example in case of formation or breaking of chemical bonds, but it arises also in optical transitions induced through light absorption by biomolecules. Quantum behavior of electrons in such cases is localized in single molecules, but it can also spread over many biomolecules in a typical quantum mechanical fashion. The biomolecules form in such case a chorus that sings in one coherent voice, rather than chatters incoherently. This type of behavior is not only of interest to the modern biological researcher, but also to modern physics researchers working on quantum computing. Three recent reviews summarize fascinating quantum behavior in biology as it comes about in vision, photosynthesis, and animal navigation using the earth's magnetic field:
In the case of vision (see July 2003, March 2002 and August 2001 highlights) twelve electrons in a molecule called retinal correlate their motion during light absorption and steer the optically excited molecule to alter its shape, thereby initiating an extremely sensitive response to light. More on vision here, here, and here.
In the case of photosynthesis (see April 2010, August 2010, March 2002 and September 2001 highlights), molecules of chlorophylls utilize thermal effects to optimally absorb sun light and then share the resulting electronic excitations among themselves through quantum coherence. More on photosynthesis can be found here and here.
In the case of animal navigation (see February 2012, July 2010, July 2009, and April 2007 highlights), quantum effects apparently bring about a magnetic compass that can sense the Earth field through its interactions of biomolecules despite the fact the interaction energy amounts to only a tiny fraction of thermal energy present at body temperature; physicists are eager to learn the trick as it might teach them how to build quantum computers without costly cooling to extremely low temperatures. More on animal navigation is available here.