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It has been postulated that photorespiration may function as a "safety valve", [23] preventing the excess of reductive potential coming from an overreduced NADPH-pool from reacting with oxygen and producing free radicals (oxidants), as these can damage the metabolic functions of the cell by subsequent oxidation of membrane lipids, proteins or ...
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]
These molecules of oxygen bind to the globin chain of the heme prosthetic group. [1] [2] When hemoglobin has no bound oxygen, nor bound carbon dioxide, it has the unbound conformation (shape). The binding of the first oxygen molecule induces change in the shape of the hemoglobin that increases its ability to bind to the other three oxygen ...
The basolateral membrane or basolateral cell membrane of a polarized cell is the surface of the plasma membrane that forms its basal and lateral surfaces. [39] It faces outwards, towards the interstitium, and away from the lumen. Basolateral membrane is a compound phrase referring to the terms "basal (base) membrane" and "lateral (side ...
Direct contact between cells allows the receptors on one cell to bind the small molecules attached to the plasma membrane of different cell. In eukaryotes, many of the cells during early development communicate through direct contact. [5] Synaptic signaling, an integral part of nervous system activity, occurs between neurons and target cells.
Bicarbonate in the red blood cell (RBC) exchanging with chloride from plasma in the lungs. The underlying properties creating the chloride shift are the presence of carbonic anhydrase within the RBCs but not the plasma, and the permeability of the RBC membrane to carbon dioxide and bicarbonate ion but not to hydrogen ion.
Calvin–Benson cycle. C 3 carbon fixation is the most common of three metabolic pathways for carbon fixation in photosynthesis, the other two being C 4 and CAM.This process converts carbon dioxide and ribulose bisphosphate (RuBP, a 5-carbon sugar) into two molecules of 3-phosphoglycerate through the following reaction:
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.