Carbon dioxide transportation, cellular

The ready reversibility of this reaction is essential to the role that qumones play in cellular respiration the process by which an organism uses molecular oxygen to convert Its food to carbon dioxide water and energy Electrons are not transferred directly from the substrate molecule to oxygen but instead are transferred by way of an electron trans port chain involving a succession of oxidation-reduction reactions A key component of this electron transport chain is the substance known as ubiquinone or coenzyme Q... 

In the chloride shift, Ck plays an important role in the transport of carbon dioxide (qv). In the plasma, CO2 is present as HCO, produced in the erythrocytes from CO2. The diffusion of HCO requires the counterdiffusion of another anion to maintain electrical neutraUty. This function is performed by Ck which readily diffuses into and out of the erythrocytes (see Fig. 5). The carbonic anhydrase-mediated Ck—HCO exchange is also important for cellular de novo fatty acid synthesis and myelination in the brain (62). 

The reactions of the electron transport chain yield most of the ATP produced by cellular respiration. These reactions take place in tiny structures within the cell called mitochondria and involve the transport of electrons. The end result of the electron transport chain is the production of 32 molecules of ATP. Thus, the total breakdown of one glucose molecule to carbon dioxide and water yields 36 molecules of ATP. 

Metabolism also produces carbon dioxide. In solution this gas forms a weak acid. Large amounts of CO, are produced by cellular activity each day with the potential to upset acid-base balance, but under normal circumstanecs all of this CO, is excreted via the lungs, having been transported in the blood. Only when... 

For substances to be chemically transported in the body, they must become part of the moving bloodstream. They may dissolve in the water-based plasma (as do sugars, amino acids, ions, and gases to some extent), they may become chemically bonded to cellular components (as do oxygen and carbon dioxide with the hemoglobin of blood cells), or they may form a suspension in the plasma of the blood (as do lipids). 

The aforementioned advantages of the extraction of compounds by supercritical fluids, especially with the application of carbon dioxide (CO2) in raw materials of plant origin, demonstrate the action of fluids on solid matrices, membrane components, cellular structures, mass transfers from inside the particle to the surface, and the mechanisms governing the transport of the substances extracted, among other recurring factors. 

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