Biological chemical reactions digestion

Waste stabilization ponds are shallow basins into which wastes are fed for biological decomposition. The chemical reactions involved are the same as those that occur in the other biological processes. Aeration is provided by the wind, and anaerobic digestion may also occur near the bottom of deeper ponds. The ponds are very commonly used for sewage treatment and dilute industrial wastes. Waste stabilization ponds are normally used as the final treatment step for effluents because they are not effieient enough to be used on their own. 

Most polypeptides and proteins are water-soluble or water swellable. Enzymes are proteins that catalyze all chemical reactions of biological origin. Enzyme functions include oxygen transport, muscle movement, nerve response, nutrient digestion and storage, hormonal regulation gene expression, and protein synthesis. 

An enzyme is a protein whose function is to serve as a catalyst for a chemical reaction within a biological system. Some functions that enzymes perform are the synthesis of proteins and other biomolecules, digestion of fats and other molecules, and sometimes they are even put to use in industrial applications outside of their natural biological environment. 

The enzymatic catalysis of reactions is essential to living systems. Under biologically relevant conditions, uncatalyzed reactions tend to be slow—most biological molecules are quite stable in the neutral-pH, mild-temperature, aqueous environment inside cells. Furthermore, many common reactions in biochemistry entail chemical events that are unfavorable or unlikely in the cellular environment, such as the transient formation of unstable charged intermediates or the collision of two or more molecules in the precise orientation required for reaction. Reactions required to digest food, send nerve signals, or contract a muscle simply do not occur at a useful rate without catalysis. 

Gas Composition. An increase in the carbon dioxide content of the gas produced has also been used to indicate the onset of digester failure. However, there is considerable variation in this with respect to time not only because of the lower damping capacity of the gas phase but also because the carbon dioxide content can be influenced by both chemical and biological reactions in the liquid phase. The normal carbon dioxide content for gas produced from domestic sewage sludge is 30-35%. 

Hydrolysis of the amide bond is the best-known reaction of this functional group, in the biological context (digestion of proteins by proteinases) as well as in the organic chemical context (aqueous hydrolysis in 6 M hydrochloric acid for 12 h at 120 °C or by dilute alkali). However, the essential role of a catalyst is made clear by the fact that a peptide dissolved in pure water survives unchanged for many months, even under reflux. 

In most chemical systems, including those of interest in biology, we are concerned with processes occurring at constant pressure rather than at constant volume. For example, all of the metabolic and digestive reactions occurring in the body occur at one atmosphere pressure and involve small changes in volume. 

---