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This is a cyclic process in which electrons are removed from an excited chlorophyll molecule (bacteriochlorophyll; P870), passed through an electron transport chain to a proton pump (cytochrome bc 1 complex; similar to the chloroplastic one), and then returned to the chlorophyll molecule. The result is a proton gradient that is used to make ATP ...
The reverse process, pair production, is the dominant mechanism by which high-energy photons such as gamma rays lose energy while passing through matter. [32] That process is the reverse of "annihilation to one photon" allowed in the electric field of an atomic nucleus.
In the process of photosynthesis, the phosphorylation of ADP to form ATP using the energy of sunlight is called photophosphorylation. Cyclic photophosphorylation occurs in both aerobic and anaerobic conditions, driven by the main primary source of energy available to living organisms, which is sunlight.
The photons of a light beam have a characteristic energy, called photon energy, which is proportional to the frequency of the light. In the photoemission process, when an electron within some material absorbs the energy of a photon and acquires more energy than its binding energy, it is likely to be ejected. If the photon energy is too low, the ...
However, photosynthesis is a quantum process and the chemical reactions of photosynthesis are more dependent on the number of photons than the energy contained in the photons. Therefore, plant biologists often quantify PAR using the number of photons in the 400-700 nm range received by a surface for a specified amount of time, or the ...
That this process is a contributing factor to spontaneous biophoton emission has been indicated by studies demonstrating that biophoton emission can be increased by depleting assayed tissue of antioxidants [17] or by addition of carbonyl derivatizing agents. [18]
An overview of absorption of electromagnetic radiation.This example shows the general principle using visible light as a specific example. A white light source—emitting light of multiple wavelengths—is focused on a sample (the pairs of complementary colors are indicated by the yellow dotted lines).
However, sustained excitation is followed by intersystem crossing to the triplet state (3 A) that relaxes to the ground state by phosphorescence with much longer decay times. In simple terms, phosphorescence is a process in which energy absorbed by a substance is released relatively slowly in the form of light.