Quantum Mechanical Effects in Biology

Abstract

Biological systems are complex and condensed. Such environments prohibit most of the quantum mechanical phenomena from surviving to play important roles but classical models work better in the biological systems. In this talk, however, I will present two spectroscopic studies to demonstrate some quantum mechanical effects that may explain ultrafast energy transfer in photosynthesis and migratory birds’ navigation. An ultrafast spectroscopic technique found that there is long-lasting electronic quantum coherence (~300 fs) between pigments inside photosynthetic reaction center. With an aid of theoretical simulation this is understood to be facilitated by proteins tightly surrounding the pigments to enhance energy transfer rates between pigments. A possibility to control some chemical reaction outcomes by a weak magnetic field will also be introduced. This kind of reactions proceeds through so called radical pair mechanism, and it is nominated as a possible mechanism in cryptochrome in their retina that allows birds to feel geomagnetic fields.