Photosynthesis and Quantum Biology

The electron excitation in the antenna (which varies between organisms) of the photosynthetic organisms enables the light absorption. The antenna of the bacteria can be in the form of the ring, while the chlorophyll pigments acts as antenna in the plants and higher organisms and its function is the absorption of the photons[1]. The most distinguishing characteristic of this excitation is the efficiency and the regulation of the time of occurrence avoiding the loss of energy because of the fluorescence. One study with the FT electron spectroscopy in the FMO complex of the green sulfur bacteria has shown an efficiency of 99% between the electrons’s absorption and the reaction site where several living intermediates occur. This high efficiency was unable to be explained by the mode of diffusion[2]. The molecules in plant whose function is to accumulate the sunlight have another function as well: the transportation of energy by the help of molecular vibrations. This behavior cannot be explained by classical physics [3]. Most of molecules that have this function consist of chromophores and proteins that can be attached to them. According to several experiments [4] the energy mode of transportation is in a wave like manner and can be explained as a quantum phenomenon. The energy exhanged in the process of photosynthesis is higher while compared to the temperature scale and it is equivalent to one unit of quantum energy[6]. Furthermore the properties displayed during the energy transfer from one chromofore to another one lack in the behaviors that can be explained by classical physics. Reasons why classical physics cannot explain those behaviors are: lack of calibration in the ground state energy and the usual removal of chemical components of leaveswhile measuring the processes such as absorption and fluorescence[7].The quantum conversions in photosynthesis include photons absorption by the molecules, such as carotene, chlorophyl a subsequent charge separation on chloroplasts. There is still a debate about whether the green color of the leaves is due to the emission or the reflection [8].  Another example of the experiements that verifies the relationship between quantum mechanics and the photosynthesis is the one whith the chromophores created by a purple dye, zinc phthalocyanine. Those chromophores were distanced by 1.5 nanometers and the red light was excited in the presence of the microscope. By using a microscope tip, the chromophores were pushed away from each other and it was noticed that a spectra of light shifting occurred [9]. In conclusion, dipole-dipole interactions affect both the biological and the photophysical processes, and those forces ‘s activity can be thoroughly explained by quantum mechanics principles [10]. 




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