Energy from carbon oxidation

Chemoautotroph An organism that obtains its energy from the oxidation of chemical compounds and uses only organic compounds as a source of carbon. Example nitrifiers. 

Sulfate and Organic Sulfates. Inorganic sulfate ion (SO L-) occurs widely in nature. Thus, it is not surprising that this ion can be used in a number of ways in biological systems. These uses can be divided primarily into two categories (1) formation of sulfate esters and the reduction of sulfate to a form that will serve as a precursor of the amino acids cysteine and methionine and (2) certain specialized bacteria use sulfate to oxidize carbon compounds and thus reduce sulfate to sulfide, while other specialized bacterial species derive energy from the oxidation of inorganic sullur compounds to sulfate. 

Chemolithotrophs organism capable of using CO2 or carbonates as the sole source of carbon for cell biosynthesis, and deriving energy from the oxidation of reduced inorganic or organic compounds. 

This. system requires reduced vitamin K (a hydroquinone. KH2). carbon dioxide, and molecular oxygen. Although the reaction docs not require ATP. it u.ses the energy from the oxidation of KH to execute the carboxylation of glutamic acid. " The carboxylase must create a carbanion by extracting a proton from the glutamate y carbon. This requires a base with a pK , of 26 to 28. The anion of the hydroquinone. however, has a pK, of only about 9. 

The nitrifying bacteria, universally found in aerobic soil and aquatic environments, derive energy from the oxidation of reduced inorganic nitrogen compounds (ammonia and nitrite). As do autotrophic bacteria, they obtain carbon from carbon dioxide in the atmosphere. 

Ketone bodies are the major fuel for the heart. Glucose is the major energy source of the brain, and the liver obtains most of its energy from the oxidation of amino acid carbon skeletons. 

In the TCA cycle, the 2-carbon acetyl group of acetyl CoA is oxidized to 2 CO2 molecules (see Fig. 20.1). The function of the cycle is to consawe the energy from this oxidation, which it accomplishes principally by transferring electrons from intermediates of the cycle to NAD and FAD. The eight electrons donated by the acetyl group eventually end up in three molecules of NADH and one of FAD(2H) (Fig. 20.2). As a consequence, ATP can be generated from oxidative phosphorylation when NADH and FAD(2H) donate these electrons to O2 via the electron transport chain. 

Chemotrophs derive free energy from the oxidation of fuel molecules, such as glucose and fatty acids. Which compound, glucose or a saturated fatty acid containing 18 carbons, would yield more free energy per carbon atom when subjected to oxidation in the cell See Figure 14.10 on page 381 for a comparison. 

Living cells derive most of their energy from the oxidation of the carbohydrate glucose, which is supplied by food from plants and indirectly from animals. Plants derive their glucose from the action of sunlight on carbon dioxide and water, in the process known as photosynthesis (see below). 

The group of microorganisms known as autotrophic bacteria obtain energy from the oxidation of a variety of inorganic compounds (ammonia, nitrite, sulfide, ferrous iron, hydrogen, carbon monoxide, sulfur, thiosulfate).The free energy changes and over-all efficiencies of a number of these processes have been calculated. We may take as an example the oxidation of nitrite to nitrate performed by Nitrobacter... 

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