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hydrogen sulfide chemosynthesis: [1] 18H 2 S + 6CO 2 + 3 O 2 → C 6 H 12 O 6 (carbohydrate) + 12H 2 O + 18 S. In the above process, hydrogen sulfide serves as a source of electrons for the reaction. [6] Instead of releasing oxygen gas while fixing carbon dioxide as in photosynthesis, hydrogen sulfide chemosynthesis produces solid globules of ...
The free energy created is then used, via a chain of nearby electron acceptors, for a transfer of hydrogen atoms (as protons and electrons) from H 2 O or hydrogen sulfide towards carbon dioxide, eventually producing glucose. These electron transfer steps ultimately result in the conversion of the energy of photons to chemical energy.
Hydrogen sulfide is often produced from the microbial breakdown of organic matter in the absence of oxygen, such as in swamps and sewers; this process is commonly known as anaerobic digestion, which is done by sulfate-reducing microorganisms. It also occurs in volcanic gases, natural gas deposits, and sometimes in well-drawn water.
Purple sulfur bacteria oxidize hydrogen sulfide (H 2 S) to sulfur (S). In oxygenic photosynthesis, water (H 2 O) serves as a substrate for photolysis resulting in the generation of diatomic oxygen (O 2). This is the process which returns oxygen to Earth's atmosphere.
In oxygenic photosynthesis, the first electron donor is water, creating oxygen (O 2) as a by-product. In anoxygenic photosynthesis, various electron donors are used. Cytochrome b 6 f and ATP synthase work together to produce ATP (photophosphorylation) in two distinct ways.
Schematic of photosynthesis in plants. The carbohydrates produced are stored in or used by the plant. Composite image showing the global distribution of photosynthesis, including both oceanic phytoplankton and terrestrial vegetation. Dark red and blue-green indicate regions of high photosynthetic activity in the ocean and on land, respectively.
The scientist Charles Barnes first used the word 'photosynthesis' in 1893. This word is taken from two Greek words, photos, which means light, and synthesis, which in chemistry means making a substance by combining simpler substances. So, in the presence of light, synthesis of food is called 'photosynthesis'.
Reduced sulfur compounds, such as hydrogen sulfide, elemental sulfur, sulfite, thiosulfate, and various polythionates (e.g., tetrathionate), are oxidized by chemotrophic, phototrophic, and mixotrophic bacteria for energy. [1] Some chemosynthetic archaea use hydrogen sulfide as an energy source for carbon fixation, producing sugars.