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Photosynthesis is the main means by which plants, algae and many bacteria produce organic compounds and oxygen from carbon dioxide and water (green arrow). An autotroph is an organism that can convert abiotic sources of energy into energy stored in organic compounds, which can be used by other organisms.
Cyanobacteria is the only prokaryotic group that performs oxygenic photosynthesis. Anoxygenic photosynthetic bacteria use PSI- and PSII-like photosystems, which are pigment protein complexes for capturing light. [5] Both of these photosystems use bacteriochlorophyll. There are multiple hypotheses for how oxygenic photosynthesis evolved.
Phototrophs can be either autotrophs or heterotrophs. If their electron and hydrogen donors are inorganic compounds (e.g., Na 2 S 2 O 3, as in some purple sulfur bacteria, or H 2 S, as in some green sulfur bacteria) they can be also called lithotrophs, and so, some photoautotrophs are also
Photo organo autotroph: Some bacteria perform anoxygenic photosynthesis and fix atmospheric carbon (Chloroflexia, Heliobacterium) Inorganic-litho-* Organic-heterotroph: Photo litho heterotroph: Purple non-sulfur bacteria: Carbon dioxide-autotroph: Photo litho autotroph: Some bacteria (cyanobacteria), some eukaryotes (eukaryotic algae, land ...
In general, photosynthesis in cyanobacteria uses water as an electron donor and produces oxygen as a byproduct, though some may also use hydrogen sulfide [79] a process which occurs among other photosynthetic bacteria such as the purple sulfur bacteria. Carbon dioxide is reduced to form carbohydrates via the Calvin cycle. [80]
In addition to photosynthetic and chemosynthetic processes, biological carbon fixation occurs in soil through the activity of microorganisms, such as bacteria and fungi. These soil microbes play a crucial role in the global carbon cycle by sequestering carbon from decomposed organic matter and recycling it back into the soil, thereby ...
Chloroplasts have many similarities with photosynthetic bacteria, including a circular chromosome, prokaryotic-type ribosome, and similar proteins in the photosynthetic reaction center. [68] [69] The endosymbiotic theory suggests that photosynthetic bacteria were acquired (by endocytosis) by early eukaryotic cells to form the first plant cells ...
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).