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Organisms that contain bacteriochlorophyll conduct photosynthesis to sustain their energy requirements, but the process is anoxygenic and does not produce oxygen as a byproduct. They use wavelengths of light not absorbed by plants or cyanobacteria. Replacement of Mg 2+ with protons gives bacteriophaeophytin (BPh), the phaeophytin form.
Bacteriochlorophyll and carotenoids are two molecules responsible for harvesting light energy. Current models of the organization of bacteriochlorophyll and carotenoids (the main constituents) inside the chlorosomes have put them in a lamellar organization, where the long farnesol tails of the bacteriochlorophyll intermix with carotenoids and each other, forming a structure resembling a lipid ...
Bacteriochlorophyll a is a typical example; its biosynthesis has been studied in Rhodobacter capsulatus and Rhodobacter sphaeroides. The first step is the reduction (with trans stereochemistry ) of the pyrrole ring B, giving the characteristic 18-electron aromatic system of many bacteriochlorophylls.
One aspect of these bacteria is that they, unlike other similar bacteria, are unable to utilize BChl (bacteriochlorophyll) for anaerobic growth. The only photosynthetic pigment that exists in AAPB is BChl-a. Anaerobic phototrophic bacteria, on the contrary, can contain numerous species of photosynthetic pigments like bacteriochlorophyll-a.
The electron transport chain of green sulfur bacteria—such as is present in the model organism Chlorobaculum tepidum—uses the reaction center bacteriochlorophyll pair, P840. When light is absorbed by the reaction center, P840 enters an excited state with a large negative reduction potential, and so readily donates the electron to ...
Photoheterotrophs generate ATP using light, in one of two ways: [6] [7] they use a bacteriochlorophyll-based reaction center, or they use a bacteriorhodopsin.The chlorophyll-based mechanism is similar to that used in photosynthesis, where light excites the molecules in a reaction center and causes a flow of electrons through an electron transport chain (ETS).
Reaction centers are present in all green plants, algae, and many bacteria.A variety in light-harvesting complexes exist across the photosynthetic species. Green plants and algae have two different types of reaction centers that are part of larger supercomplexes known as P700 in Photosystem I and P680 in Photosystem II.
Bacteriochlorophyll, related compounds in phototrophic bacteria; Chlorophyllin, a semi-synthetic derivative of chlorophyll; Deep chlorophyll maximum; Chlorophyll fluorescence, to measure plant stress; Purple Earth hypothesis, a scientific hypothesis that explains the evolution of red-blue spectral affinity of chlorophyll.