Respiration process

Ubiquinones function within the mitochondria of cells to mediate the respiration process in which electrons are transported from the biological reducing agent NADH to molecular oxygen. Through a complex series of steps, the ultimate result is a cycle whereby NADH is oxidized to NAD+, O2 is reduced to water, and energy is produced. Ubiquinone acts only as an intermediary and is itself unchanged. 

Carbon Dioxide. Carbon dioxide, also a colorless and odorless gas, makes up about 0.03% of dry air. Carbon dioxide is introduced into the atmosphere by several natural processes it is released from volcanoes, from burning organic matter, and from living animals as a byproduct of the respiration process. It is for this latter reason that carbon dioxide plays a vital role in the carbon cycle (see Fig. 62), which makes possible one of the more important scientific tools in archaeology, radiocarbon dating (see Textbox 52). 

These energy-producing reactions are termed respiration processes. They require the presence of an external compound that can serve as the terminal electron acceptor of the electron transport chain. However, under anaerobic conditions, fermentation processes that do not require the participation of an external electron acceptor can also proceed. In this case, the organic substrate undergoes a balanced series of oxidative and reductive reactions, i.e., organic matter reduced in one step of the process is oxidized in another. 

As shown in Figure 6.8, the most important part of the anaerobic sulfur cycle in terms of the sulfate respiration process can be integrated with the anaerobic carbon cycle. A fractionation of the readily biodegradable substrate (Ss) into SF and SA fits well to the anticipation that mainly SF is used by the sulfate-reducing biomass in sewer biofilms. By integrating the sulfide formation in this way, a simple conceptual approach is obtained instead of the traditional empirical descriptions as depicted in Table 6.1. 

Highly halogenated organic compounds such as polychlorinated biphenyls and perchloroethylene appear to be too highly oxidised and low in energy content to serve as sources of electrons and energy for microbial metabolism. Bacteria are more likely to use them as electron acceptors in cell-membrane-based respiration processes [154]. The environmental fate of halogenated polymers such as polyvinylchloride or Teflon may depend on the question of whether it will be appropriate to sustain de-halorespiration processes. 

The intracellular modification or degradation of the substrate by metabolic sequences of enzymatic systems under aerobic conditions in connection with the respiration processes. These processes result in an increased respiratory rate. 

Trichosporon cutaneum [89]. The principle of this method is based on the measurement of the rapid alteration (or acceleration) of respiration after addition of ammonium ions in the presence of glucose. The physiological background of this principle is probably the uptake of ammonium ions in connection with the respiration process. Finally, the combination of nitrifying bacteria with urease on a hybrid sensor also allows an amperometric determination of urea [93]. 

The amount of oxygen in the atmosphere remains fairly constant at about 1.18 X 1018 kg because the combustion and respiration processes that remove 02 are balanced by photosynthesis, the complex process in which green plants use solar energy to produce 02 and glucose from carbon dioxide and water ... 

Hydrocarbons (HCs) or Volatile Organic Compounds (VOCs). These are derived primarily from two sources approximately 50% are derived from trees as a result of the respiration process (biogenic) the other 45% to 50% comes from the combustion of fuel and from vapor from gasoline. Many gasoline pumps now have VOC recovery devices to reduce pollution. 

The electron is consecutively transferred from one respiratory chain unit to another and, finally, occurs on molecular oxygen. Therefore, it may not participate as a material particle in any other reaction outside the framework of the respiration process. 

Actually, if we denote rates of water production in the respiration process and ATP synthesis during phosphorylation by rD and rph, respectively, the following ratios of the rates may be obtained ... 

Let us analyze the ATP synthesis reaction (3.50), which, with respect to inorganic phosphate ion charge, requires one or two H+ ions for oxidation reaction. Figure 3.4 clearly illustrates that the H+-ATP-synthase responsible for oxidative phosphorylation consumes active H30+ particles (H+ ion) from both parts of the reaction system (matrix and cytoplasm). Specifying the work of H+-ATP-synthase, it should be noted that H+ ions delivered from the cytoplasm to the membrane and ADP and P substrates participate in phosphorylation reaction proceeding on the internal surface of the membrane. In this case, water molecules are one of the products of oxidative phosphorylation. It does not release to the volume, but dissociates to H + and OH ions immediately on the membrane. Then according to the chemiosmotic mechanism OH anion is desorbed to cytoplasm and H+ ion to the matrix, where its occurrence as the active particle is associated with water production at the final stage of the respiration process. 

The respiration process produces electric potential difference on the membrane, and then H+ ion concentration gradient is formed on the membrane sides, which plays the important role in H+ ion transport. 

As discussed above, active particles H+ + e are generated in the Krebs cycle during the respiration process. These particles then participate in water formation, which is the secondary reaction product. 

Here curve I corresponds to water formation at a maximum rate in the respiration process. Since H+ and e formation is the general process for conjugated processes, their synchronization mechanism may be presented by the following scheme ... 

The system operates in the membrane catalysis mode. Therefore, as shown in the scheme, the parallel reaction does not run by the first pathway, but implements the consecutive means of water molecule formation in the respiration process. 

The tendency of cyanide ion to bond with iron(III) is responsible for its toxicity in that it bonds with iron(III) in one of the enzymes involved in the utilization of molecular oxygen in respiration processes.) This prevents utilization of oxygen with potentially fatal results, as discussed in Chapter 11.) The species that bonds to the metal ion, cyanide in this case, is called a ligand, and the product of the reaction is a complex ion or metal complex. The overall process is called complexation. 

Adverse effects on metabolic processes constitute a major mode of action of toxic substances. For example, cyanide ion bonds with ferricytochrome oxidase, a form of an enzyme containing iron(III) that cycles with ferrouscytochrome oxidase, containing iron(II), in the respiration process by which molecular oxygen is utilized, thus preventing the utilization of 02 and leading to rapid death. 

Regarding organic acids metabolism, Amati et al. (1983) reported that malic acid is consumed in both natural and conditioned systems, although it was more intense in the latter. This malic acid decrease is probably due to the respiration processes and /or to malic acid conversion into sugar (gluconeogenesis). In contrast, tartaric acid decreases slightly, and no differences were seen between the two drying systems. 

The main source of carbon monoxide, aside from the fossil fuel burning flux, is ffom oxidation of CH4 (Table 9.3). The remainder comes ffom decomposition of organic matter in soils, and bacteria and algae in the ocean that actively generate CO from respiration processes according to ... 

As nonconservative gases, carbon dioxide and oxygen are closely coupled to the organic carbon pool through autotrophic (e.g., photosynthesis) and heterotrophic (e.g., respiration) processes. The dominant primary producers in estuaries and the coastal ocean are benthic and pelagic microalgae (phytoplankton). The average atomic C-to-N-to-P ratio... 

Respiration process by which oxygen is taken in and used by tissues in the body and carbon dioxide is released. 

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