Comparing The Adaptations For Nitrogenous Excretion Across Three Taxonomic Groups

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Report Comparing the Adaptations Relating to Nitrogenous Excretion across Three Taxonomic Groups

All organisms produce waste nitrogen products as part of their metabolism. Nitrogen is obtained from the diet in the form of protein and nucleic acids. When a protein is ingested, the tertiary and secondary structures of the protein are denatured. The peptide bonds are also broken, separating the protein into individual amino acids, the basic structure of which is displayed in Fig. 1.1.

Amino acids are used to synthesise variety of functional compounds, including nucleic acids and enzymes. However, when amino acids are obtained in the diet in excess of those needed for synthesis of functional nitrogenous compounds, they are either catabolised as energy sources or used as sources of carbon chains for synthesis of non-nitrogenous storage compounds. When amino acids are used as energy sources or for the synthesis of non-nitrogenous compounds, the nitrogenous component of the acid must first be removed. The amino group, -NH₂, is the nitrogenous component of protein and is removed from the amino acid by a catabolic process called deamination. This process removes the amino group from the amino acid and converts it to ammonia (NH₃).

The ammonia is highly toxic and must either be excreted quickly or converted to a less toxic waste product, such as urea or uric acid, and then excreted. Organisms that excrete nitrogen as ammonia (Fig. 1.2) are ammonotelic. Organisms that convert

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