Respiration consumers

Three processes that take place in living organisms - respiration in animals and plants, photosynthesis only in plants, and the precipitation of solids by some aquatic animals - have altered the primeval composition of the outer solid, liquid, and gaseous layers of the earth. Respiration consumes oxygen from the atmosphere and creates carbon dioxide. Photosynthesis, which does the opposite (consumes carbon dioxide and releases oxygen), has... 

In the dark, plants also carry out mitochondrial respiration, the oxidation of substrates to C02 and the conversion of 02 to H20. And there is another process in plants that, like mitochondrial respiration, consumes 02 and produces C02 and, like photosynthesis, is driven by light. This process, photorespiration, is a costly side reaction of photosynthesis, a result of the lack of specificity of the enzyme rubisco. In this section we describe this side reaction and the strategies plants use to minimize its metabolic consequences. 

Figure 6. An idealized scheme for a sedimentary porous medium with pore walls covered by a biofilm. High sulfate reduction rates are maintained even in depths to which sulfate cannot diffuse because of recycling of sulfate within the biofilm. Numbered points (in black circles) denote the following processes I, Respiration consumes oxygen. 2, Microbial reduction of reactive metal Oxides. Reduction of reactive ferric oxides is in equilibrium with reoxidation of ferrous iron by Os. Thus, no net loss of reactive iron takes place in these layers. 3, Microbial reduction of ferric oxides. 4, Sulfate reduction rate (denoted as SRR). 5, Sulfide oxidation, either microbiologically or chemically. 6, Sulfide builds up within the hiofilm, sulfate consumption increases, reactive iron pool decreases. 7, Formation of iron sulfides.

The concept of nutrient and O2 change along a surface of constant density in the upper ocean is illustrated in Fig. 6.18. When waters subduct (surface waters flow along density horizons into the thermo-cline) it is assumed that they carry with them O2 concentrations near saturation equilibrium with the atmosphere and preformed nutrient concentrations. The assumption of saturation equihbrium is not exactly correct but in most cases this is probably not a serious error because surface oxygen measurements indicate near-saturation equilibrium everywhere except in the Southern Ocean south of the polar front, where concentrations can be up to 10% undersaturated. As a water parcel moves along a constant-density surface into the upper thermocline, respiration consumes the O2 concentration while creating nutrients and AOU in the water mass. At any point in the ocean interior, preformed nutrient concentrations can be calculated if one knows the temperature, salinity (for determining [02 ), nutrient and O2 concentrations. 

A useful index of process performance is the oxygen uptake rate, OUR, that is calculated from the difference in oxygen concentration of the inlet air and the exiting gas. Also important is the respiration ratio defined as the carbon dioxide evolved divided by the oxygen consumed. 

The Costs of Locomotion. Because oxygen is required for energy-producing metabolic reactions (respiration), there is a direct correlation between the amount of oxygen consumed and the metabolic rate. Not surprisingly, metabolic rates increase with activity. During exercise, a person will consume fifteen to twenty times more oxygen than when at rest. 

Like all matter, carbon can neither be created nor destroyed it can just be moved from one place to another. The carbon cycle depicts the various places where carbon can be found. Carbon occurs in the atmosphere, in the ocean, in plants and animals, and in fossil fuels. Carbon can be moved from the atmosphere into either producers (through the process of photosynthesis) or the ocean (through the process of diffusion). Some producers will become fossil fuels, and some will be eaten by either consumers or decomposers. The carbon is returned to the atmosphere when consumers respire, when fossil fuels are burned, and when plants are burned in a fire. The amount of carbon in the atmosphere can be changed by increasing or decreasing rates of photosynthesis, use of fossil fuels, and number of fires. 

The fruits are loaded and the store sealed. Within a few days they consume a proportion of the available oxygen and respire carbon dioxide. Considerable research over the past 60 years, mainlyin the UK [47], has determined the correct balance of gases to prolong the storage life of the different varieties of apples and pears, both home grown and imported. 

Certain stored foodstuffs are living organisms and give off heat as their sugar or starch reserves are slowly consumed. This is known as the heat of respiration, since the products consume oxygen for the... 

Active transport is of basic importance for life processes. For example, it consumes 30-40 per cent of the metabolic energy in the human body. The nervous system, which constitutes only 2 per cent of the weight of the organism, utilizes 20 per cent of the total amount of oxygen consumed in respiration to produce energy for active transport. 

Historically, measurement of the microbial biomass has been a tedious, time-consuming occupation involving staining and direct counting or use of culture media and enumeration of individual microbial communities. However, in the last 20 years, a suite of methods have been developed for more rapid assessment of the microbial biomass. These include the substrate-induced respiration method (Anderson and Domsch 1978), the chloroform fumigation-incubation method (Jenkinson and... 

The P/O ratio is the number of ATPs made for each O atom consumed by mitochondrial respiration. The P stands for high-energy phosphate equivalents, and the O actually stands for the number of I 02 s that are consumed by the electron transport chain. The full reduction of 02 to 2 H20 takes 4 electrons. Therefore, 2 electrons reduce of an 02. The oxidation of NADH to NAD and the oxidation of FADH2 to FAD are both 2-electron oxidations. O can be read as the transfer of 2 electrons. It s not quite as obscure as it sounds.2... 

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