Adenosine triphosphate energy production

Chlorophenols block adenosine triphosphate (ATP) production, without blocking the electron transport chain. They inhibit oxidative phosphorylation, which increases basal metabolic rate and increases body temperature. As body temperature rises, heat-dissipating mechanisms are overcome and metabolism is accelerated. Adenosine diphosphate (ADP) and other substrates accumulate, and stimulate the electron transport chain further. This process demands more oxygen in a futile effort to produce ATP. Oxygen demand quickly surpasses oxygen supply and energy reserves of the body become depleted. 

An energy deficit [i.e., loss of adenosine triphosphate (ATP) production) reduces active transport and control of cell electrolytes and water. Synthesis of enzymes or structural proteins may be reduced. 

Figure 29.1 An overview of catabolic pathways for the degradation of food and the production of biochemical energy. The ultimate products of food catabolism are C02 and H2O, with the energy released in the citric acid cycle used to drive the endergonic synthesis of adenosine triphosphate (ATP) from adenosine diphosphate (ADP) plus phosphate ion, HOPO32-.

The process occurring in plants and algae by which water is oxidized to molecular oxygen and carbon dioxide is converted to carbohydrates in the presence of light is called photosynthesis. In addition to the products oxygen and carbohydrate, light energy is stored chemically in adenosine triphosphate (ATP) for later use for a variety of purposes. The production of... 

Mitochondrial heterogeneity leads to multiple simultaneous TCA cycles in astrocytes and neurons 546 Partial TCA cycles can provide energy in brain 546 Adenosine triphosphate production in brain is highly regulated 546 Phosphocreatine has a role in maintaining adenosine triphosphate levels in brain 546... 

The energy released is used to transfer protons across the photosynthetic membrane and ultimately this energy acts as a driving force for the catalysed production of high-energy adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate. 

In some cases, enzymes require the assistance of coenzymes (cofactors) to ensure the reactions proceed. Coenzymes include vitamins, metal ions, acids, and bases. They can act as transporters or electron acceptors or be involved in oxidation-reduction reactions. At the completion of the reaction, coenzymes are released, and they do not form part of the products. For some reactions that are energetically unfavorable, an energy source provided by the compound adenosine triphosphate (ATP) is needed to ensure the reactions proceed, as shown in the following reactions ... 

Mitochondria are found in the cell body and all processes of the neuron. They possess a double membrane and their own DNA and they play a role in cellular respiration and energy synthesis. Mitochondria contain enzymes essential for energy production in the form of adenosine triphosphate (ATP). 

Note that equation 5.2 is irreversible and the product AMP will require two phosphorylation steps to reconstitute the high-energy adenosine triphosphate, ATP. Inositol 1,4,5-triphosphate is an important molecule in the cytosol, where it releases calcium ions from storage. It forms part of a series of inositol-phosphate species that mediate calcium ion concentrations inside and outside the cell. 

Since active transport often requires energy in the form of adenosine triphosphate (ATP), compounds or conditions that inhibit energy production (e.g., iodoac-etate, fluoride, cyanide, anaerobiosis) will impair active transport. The transport of a given compound also can be inhibited competitively by the coadministration of other compounds of sufficient structural similarity that they can compete with the first substance for sites on the carrier protein. 

An important role is played by adenosine triphosphate (ATP), involved in energy exchange relatively large amounts of free energy are released when ATP is hydrolyzed. A consequence of the loss of ATP in muscle postmortem is its conversion to hypoxanthine. Some 5 -mononucleotides, intermediates in the production of hypoxanthine and with the ribose component hy-droxylated at position 6, are flavor enhancers in muscle foods. Compounds of this kind are, for example, inosine 5 -monophosphate (IMP) and guanosine 5 -monophosphate (GMP). The ATP is first converted to ADP and then to AMP by a disproportionation reaction. The AMP is then de-aminated to IMP. The IMP can degrade to inosine and eventually to hypoxanthine. Hypoxanthine... 

These compounds vary, from the natural product rotenone (from Derris or Lonchocarpus root, used to control vegetable and fruit insects) to the synthetics sulfluramid and hydramethylnon (used to control mites and cockroaches). Interestingly, the highest acute toxicity to mammals is caused by the natural product rotenone. These compounds affect the production of adenosine triphosphate (ATP), the energy storage molecule of the cell that is produced by mitochondria, the powerhouse of the cell. The disruption of energy metabolism and the subsequent loss of ATP result in a slowly developing toxicity, and the effects of all these compounds include inactivity, paralysis, and death. 

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