Respiration aerobic

Respiration, or biological oxidation, is the use of oxygen as an electron receptor in the cataboHc degradation of an organic and can occur either aerobically or anaerobically. Aerobic respiration uses free oxygen as an electron receptor whereas anaerobic respiration uses inorganic oxygen. In both cases, however, water and carbon dioxide are the principal end products. 

Aerobic (i) Having molecular oxygen as a part of the environment, (ii) Growing only in the presence of molecular oxygen, as in aerobic organisms, (iii) Occurring only in the presence of molecular oxygen, as in certain chemical or biochemical processes such as aerobic respiration. 

Aerobic respiration. Many organisms carry out aerobic respiration in which enzymes remove electrons from organic compounds and pass them through a chain of carriers including flavoproteins and cytochromes located in intracellular membranes (Fig. 3-4) until finally they are used to reduce oxygen to produce water. ATP is produced by an enzyme called ATPase, that is located in the cell membrane, and the process is driven by a proton gradient across the membrane. 

If aerobic respiration continues to completion, all of the organic material is oxidized to form carbon dioxide and water. Much more energy is... 

Aerobic respiration (organic All plants, animals, and strictly aerobic... 

When a technical language is adopted by those who do not share the expertise of its parent community, it may actually become distorted, and this may make it even more difficult for students to keep clear what different forms of symbolism mean. So in biology lessons students are likely to meet equations representing photosynthesis and aerobic respiration (Examples 7 and 8 in Table 4.1). When just considering the substances involved, these two equations will seem to stand in the same relation as those discussed for the hydrogen/nitrogen-ammonia equilibrium ... 

SRB, a diverse group of anaerobic bacteria isolated from a variety of environments, use sulfate in the absence of oxygen as the terminal electron acceptor in respiration. During biofilm formation, if the aerobic respiration rate within a biofilm is greater than the oxygen diffusion rate, the metal/biofilm interface can become anaerobic and provide a niche for sulfide production by SRB. The critical thickness of the biofilm required to produce anaerobie conditions depends on the availability of oxygen and the rate of respiration. The corrosion rate of iron and copper alloys in the presence of hydrogen sulfide is accelerated by the formation of iron sulfide minerals that stimulate the cathodic reaction. 

Figure 18.2 Summary of respiratory energy flows. Foods ate converted into the reduced form of nicotinamide adenine dinucleotide (NADH), a strong reductant, which is the most reducing of the respiratory electron carriers (donors). Respiration can he based on a variety of terminal oxidants, such as O2, nitrate, or fumarate. Of those, O2 is the strongest, so that aerobic respiration extracts the largest amount of free energy from a given amount of food. In aerobic respiration, NADH is not oxidized directly by O2 rather, the reaction proceeds through intermediate electron carriers, such as the quinone/quinol couple and cytochrome c. The most efficient respiratory pathway is based on oxidation of ferrocytochrome c (Fe ) with O2 catalyzed by cytochrome c oxidase (CcO). Of the 550 mV difference between the standard potentials of c)Tochrome c and O2, CcO converts 450 mV into proton-motive force (see the text for further details).

Facultative anaerobe An organism that makes adenosine triphosphate by aerobic respiration if oxygen is present, but switches to fermentation under anaerobic conditions. 

Aerobic respiration, in which oxygen is required as a terminal electron acceptor... 

Aerobic respiration Denitrification Mn(IV) reduction Fe(III) reduction Sulfate reduction Methane fermentation Nitrogen fixation... 

Fig. 6.5 Microbial iron and sulfur cycles that may have dominated biogeochemical cycling before the origin of oxygenic photosynthesis, aerobic respiration and possibly before the use of oxides of nitrogen.

Spheromorph Acritarchs, primitive unicellular eukaryotes Atmosphere oxidising Endosymbiosis. Aerobic respiration 0.3%... 

Red algae and metaphytes Large cells. Endosymbiosis. Aerobic respiration. Meiosis. Genetic recombination 0.5%... 

As a result, the partial breakdown of the organic matter by fermentation yields organic products with a low molecular weight, e.g., VFAs, along with C02. Compared with the aerobic respiration, the fermentation is inefficient however, these fermentation products can to some extent, and in addition to fermentable substrate, be used by the sulfate-reducing bacteria that make use of sulfate as the terminal electron acceptor (Nielsen and Hvitved-Jacobsen, 1988). In the absence of sulfate, the methanogenic bacteria utilize the low molecular... 

Anaerobic conditions prevail in full-flowing gravity sewers and pressure mains. In cases where aerobic wastewater flows into such sewers, the DO concentration is typically fast depleted, often after 10-30 minutes, depending on the level of the DO concentration and the aerobic respiration rate of the wastewater. Although sulfide problems in sewer networks are particularly widespread in countries with high temperatures, it may also occur in pressure mains during winter under temperate climate conditions, i.e., at temperatures around 5-12°C (Hvitved-Jacobsen et al 1995 Nielsen et al 1998). Under such low temperature conditions, the sulfide production rate is low, and the anaerobic residence time should typically exceed 0.5-2 hours before sulfide production is significant. 

It is important to note that the amount of oxygen needed to avoid sulfate-reducing conditions is determined by the aerobic respiration rate of the wastewater and the biofilm and not the potential amount of total sulfide production in the sewer. The relatively low solubility of oxygen (9-11 g02 m-3) in wastewater compared with the DO consumption rate typically requires that oxygen must be injected at several points of a sewer pipe to ensure aerobic conditions. This is, of course, expensive and requires manpower in terms of operation and maintenance. Furthermore, the readily biodegradable and fast hydrolyzable fractions of the organic matter may be depleted (Tanaka et al., 2000b). In the case of requirement for mechanical treatment, this is positive ... 

In the case of fermentation, the carbon and energy source is broken down by a series of enzyme-mediated reactions that do not involve an electron transport chain. In aerobic respiration, the carbon and energy source is broken down by a series of enzyme-mediated reactions in which oxygen serves as an external electron acceptor. In anaerobic respiration, the carbon and energy source is broken down by a series of enzyme-mediated reactions in which sulfates, nitrates, and carbon dioxide serve... 

The bacterium Pseudomonas denitrificans is capable of this kind of metabolism utilizing nitrate as a terminal electron acceptor rather than oxygen. This bacterium can use oxygen as a terminal electron acceptor if it is available, and aerobic respiration is more efficient than anaerobic respiration. 

Oxidants are also naturally present in the body, where they participate in important redox reactions. For example, mitochondria consume oxygen during aerobic respiration, and cells ingest and destroy bacteria. Both these processes involve oxidation and reduction. 

At least from the time of van Helmont on, the chemists when separating and describing gases usually examined the effect of the gases on animals and plants. Lavoisier (1777) understood that aerobic respiration is the process in which oxygen is consumed and carbon dioxide is produced, shortly after the discovery of oxygen (1771). However, it took about half a century to make aerobic respiration more comprehensible from a physical point of view (Joule 1843 Mayer 1845 and many others). 

DUling W, Cypionka H. 1990. Aerobic respiration in sulfate-reducing bacteria. FEMS Microbiol Lett 71 123-8. 

This model was first applied to dissolved oxygen gas (O2) profiles to estimate the rate of aerobic respiration. This biological process is responsible fiar the presence of a pronounced mid-depth O2 concentration minimum in the mid- and low latitudes throughout all the ocean basins. The concentration minimum in the Atlantic can be seen in Figure 4.l4e. The solution to Eq. 4.14, in the presence of an upward vertical advection, is... 

---