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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.
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.
CO 2 is excreted from the cell via diffusion into the blood stream, where it is transported in three ways: Up to 7% is dissolved in its molecular form in blood plasma. About 70-80% is converted into hydrocarbonate ions, The remainder binds with haemoglobin in red blood cells, is carried to the lungs, and exhaled. [11]
In plants, 2-phosphoglycolate has a potentially toxic effect as it inhibits a number of metabolic pathways. [3] The activities of important enzymes in the central carbon metabolism of the chloroplast such as triose-phosphate isomerase, phosphofructokinase, or sedoheptulose 1,7-bisphosphate phosphatase show a significant decrease in the presence of 2-PG.
The reactive enodiolate species is also sensitive to oxygen (O 2), which results in the dual carboxylase / oxygenase activity of RuBisCO. [13] This reaction is considered wasteful as it produces products (3-phosphoglycerate and 2-phosphoglycolate) that must be catabolized through photorespiration. [14]
Winter brings less daylight and colder temperatures, which can disrupt sleep. Seasonal Affective Disorder (SAD) is more common in winter due to the lack of sunlight, causing sleep disturbances.
For multicellular organisms, during short bursts of strenuous activity, muscle cells use fermentation to supplement the ATP production from the slower aerobic respiration, so fermentation may be used by a cell even before the oxygen levels are depleted, as is the case in sports that do not require athletes to pace themselves, such as sprinting.
The process of breathing does not fill the alveoli with atmospheric air during each inhalation (about 350 ml per breath), but the inhaled air is carefully diluted and thoroughly mixed with a large volume of gas (about 2.5 liters in adult humans) known as the functional residual capacity which remains in the lungs after each exhalation, and ...