2 26.1 Biosynthesis of Amino Acids Essential Amino AcidsIle Leu Lys MetPhe Thr Trp ValThe amino acids can be grouped together into six biosynthetic pathways depending on the intermediate from which they are derived.
3 TCA CYCLEa-Ketoglutarate OxaloacetateGlu AspGln Pro Arg Asn Met Thr Lysa-Ketoglutarate Ilefamily( Glutamate family) Aspartate family
4 GLYCOLYSIS3-Phosphoglycerate PyruvateSerAla Val LeuCys Gly Pyruvate family3-Phosphoglyceratefamily( Serine family)
6 26.2 Amino Acid Degradation The amino acids are degraded by 20 different pathways that converge to just 7 metabolic intermediatesPyruvatea-Ketoglutarate Succinyl-CoAFumarate OxaloacetateAcetyl-CoA Acetoacetate
13 The excess nitrogen is first converted into ammonia and is the excreted from living organisms in one of three ways.Many aquatic animals simply excrete the ammonia itself directly into the surrounding water. Birds and terrestrial reptiles excrete the ammonia in the form of uric acid, while most terrestrial vertebrates convert the ammonia into urea before excretion.These three classes of organisms are called: ammonotelic, uricotelic and ureotelic, respectively.