Abstract. The photosystem II (PSII) light-harvesting system car- ries out two essential functions, the efficient collection of light energy for photosynthesis, and the. Researchers in the UK and France have developed a dye-based molecule that mimics the light harvesting complex found in plants. The system. The light-harvesting complex (or antenna complex) is an array of protein and chlorophyll molecules embedded in the thylakoid membrane of plants, which.
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LIGHT HARVESTING ANTENNA PDF
They used boron dipyrromethene Light harvesting antenna dyes and pyrene which appears to prevent photon loss and avoid formation of the highly energetic states that typically degrade a device.
When photons are absorbed at the periphery of the array, they cascade towards a terminal acceptor but their arrival is staggered as they move between chromophores.
Excess protons that accumulate in the lumen see above can 1 stimulate the deepoxidation of V, and 2 protonate one or more of the antenna complexes of PSII. The possibility light harvesting antenna a photochemical component of fluorescence quenching at saturating light, involving a photoprotective role for O2 as an electron sink, has been discussed recently by Ort and Baker As fluorescence yield decreases, the yield of thermal dissipation increases.
Figure 1 is a generalized but all-inclusive scheme of some of the possibilities involved in the chemistry and components of the light harvesting antenna switch.
More research is needed to clearly define the mechanistic aspects of this process. High light results in lumen acidification, which in turn stimulates changes in the antenna of PSII that promote thermal dissipation.
Light-harvesting complex - Wikipedia
These complexes all have been implicated as sites of thermal dissipation. The acidification also stimulates the deepoxidation of V to Z. Figure courtesy of Dafna Elrad. Chlorophyll b is almost identical to chlorophyll a except it has a formyl group light harvesting antenna place of a methyl group.
Carotenoids are long linear organic molecules that have alternating single and double bonds along their length. Such molecules are called polyenes.
Due to their absorption light harvesting antenna, carotenoids appear red and yellow and provide most of the red and yellow colours present in fruits and flowers.
The carotenoid molecules also serve a safeguarding function. Their absorption spectra are non-overlapping and broaden the range of light that can be absorbed in photosynthesis. The carotenoids have another role as an antioxidant to light harvesting antenna photo-oxidative damage of chlorophyll molecules.