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Photorespiration may be necessary for the assimilation of nitrate from soil. Thus, a lowering in photorespiration by genetic engineering or because of increasing atmospheric carbon dioxide may not benefit plants as has been proposed. [13] Several physiological processes may be responsible for linking photorespiration and nitrogen assimilation.
One efficiency-focused research topic is improving the efficiency of photorespiration. Around 25% of the time RuBisCO incorrectly collects oxygen molecules instead of CO 2, creating CO 2 and ammonia that disrupt the photosynthesis process. Plants remove these byproducts via photorespiration, requiring energy and nutrients that would otherwise ...
C3 carbon fixation is prone to photorespiration (PR) during dehydration, accumulating toxic glycolate products. In the 2000s scientists used computer simulation combined with an optimization algorithm to figure out what parts of the metabolic pathway may be tuned to improve photosynthesis.
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]
2 in photorespiration. The rate of photorespiration is higher at high temperatures. Photorespiration turns RuBP into 3-PGA and 2-phosphoglycolate, a 2-carbon molecule that can be converted via glycolate and glyoxalate to glycine. Via the glycine cleavage system and tetrahydrofolate, two glycines are converted into serine plus CO 2. Serine can ...
In other bacteria, different mechanisms like the reverse Krebs cycle are used to achieve the same end. The first photosynthetic organisms probably evolved early in the evolutionary history of life using reducing agents such as hydrogen or hydrogen sulfide, rather than water, as sources of electrons. [4]
The enzyme RuBisCO is responsible for "fixing" CO 2 – that is, it attaches it to a carbon-based molecule to form a sugar, which can be used by the plant, releasing an oxygen molecule along the way. However, the enzyme is notoriously inefficient, and just as effectively will also fix oxygen instead of CO 2 in a process called photorespiration.
Photorespiration can occur when the oxygen concentration is too high. RuBisCO cannot distinguish between oxygen and carbon dioxide very well, so it can accidentally add O 2 instead of CO 2 to RuBP. This process reduces the efficiency of photosynthesis—it consumes ATP and oxygen, releases CO 2, and produces no sugar.