|text = Amino acids are the structural components of proteins in all plants, animals and fungi. Amino acids are considered either indispensable ('''essential''') and dispensable ('''non-essential''').
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*Essential amino acids are those that are required pre-formed in the diet as the animal either lacks the metabolic pathway to synthesise the given amino acid or is unable to make sufficient quantities for growth and normal physiologic/biochemical functions.
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*Non-essential amino acids are those that can be produced endogenously from available nitrogen and carbon sources.