Search results
Results from the WOW.Com Content Network
Biological carbon fixation, or сarbon assimilation, is the process by which living organisms convert inorganic carbon (particularly carbon dioxide) to organic compounds. These organic compounds are then used to store energy and as structures for other biomolecules .
In high-temperature and low-oxygen environments, the 3-HP/4-HB cycle uses less energy than the Calvin cycle, which is common in plants and algae. The 3-HP/4-HB cycle is a perfect method for energy conservation in archaea compared to the Calvin cycle since it fixes carbon with fewer ATP molecules.
In oxic solutions, high O 2 concentrations reduce the efficiency of CO 2 fixation and result in the excretion of glycolate. Under these conditions, clumping can be beneficial to cyanobacteria if it stimulates the retention of carbon and the assimilation of inorganic carbon by cyanobacteria within clumps.
Many photosynthetic life forms (plants, algae, phototrophic and chemoautotrophic bacteria, and archaea) require a way to utilize carbon into their metabolic pathways.This usually occurs in pathways that fix carbon from carbon dioxide (CO 2).
Cross section of a Chlamydomonas reinhardtii algae cell, a 3D representation. Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae, [1] and in a single group of land plants, the hornworts. [2] Pyrenoids are associated with the operation of a carbon-concentrating mechanism (CCM).
Some plants, many algae, and photosynthetic bacteria have overcome this limitation by devising means to increase the concentration of carbon dioxide around the enzyme, including C 4 carbon fixation, crassulacean acid metabolism, and the use of pyrenoid. Rubisco side activities can lead to useless or inhibitory by-products.
Marine phytoplankton form the basis of the marine food web, account for approximately half of global carbon fixation and oxygen production by photosynthesis [14] and are a key link in the global carbon cycle. [15]
Carbon on Earth naturally occurs in two stable isotopes, with 98.9% in the form of 12 C and 1.1% in 13 C. [1] [8] The ratio between these isotopes varies in biological organisms due to metabolic processes that selectively use one carbon isotope over the other, or "fractionate" carbon through kinetic or thermodynamic effects. [1]