Search results
Results from the WOW.Com Content Network
The important sulfur cycle is a biogeochemical cycle in which the sulfur moves between rocks, waterways and living systems. It is important in geology as it affects many minerals and in life because sulfur is an essential element (), being a constituent of many proteins and cofactors, and sulfur compounds can be used as oxidants or reductants in microbial respiration. [1]
Sulfur reduction occurs in plants, fungi, and many bacteria. [10] Sulfate can serve as an electron acceptor in anaerobic respiration and can also be reduced for the formation of organic compounds. Sulfate-reducing bacteria reduce sulfate and other oxidized sulfur compounds, such as sulfite, thiosulfate, and elemental sulfur, to sulfide.
Anoxygenic photosynthesis is a special form of photosynthesis used by some bacteria and archaea, which differs from the better known oxygenic photosynthesis in plants in the reductant used (e.g. hydrogen sulfide instead of water) and the byproduct generated (e.g. elemental sulfur instead of molecular oxygen).
Photosynthesis occurs in two stages. In the first stage, light-dependent reactions or light reactions capture the energy of light and use it to make the hydrogen carrier NADPH and the energy-storage molecule ATP. During the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide.
Referring to the latest definition, Chromatiaceae family includes only those purple sulfur bacteria that perform anoxygenic photosynthesis and store elemental sulfur inside their cells. This is in line with the first Molisch definition of the Thiorhodaceae group and reflects the distance, but phylogenetic correlation between the two families. [11]
Studies have actually demonstrated that the two wavelengths together have a synergistic effect on the photosynthetic activity, rather than an additive one. [1] Each photosystem has two parts: a reaction center, where the photochemistry occurs, and an antenna complex, which surrounds the reaction center.
Light-dependent reactions of photosynthesis at the thylakoid membrane. Light-dependent reactions are certain photochemical reactions involved in photosynthesis, the main process by which plants acquire energy. There are two light dependent reactions: the first occurs at photosystem II (PSII) and the second occurs at photosystem I (PSI).
Sulfur is a structural component of some amino acids (including cystein and methionine) and vitamins, and is essential for chloroplast growth and function; it is found in the iron-sulfur complexes of the electron transport chains in photosynthesis.