The ATP yield for every oxidation cycle is theoretically a maximum yield of 17, as NADH produces 3 ATP, FADH 2 produces 2 and a full rotation of the citric acid cycle produces 12. [ citation needed ] In practice it's closer to 14 ATP for a full oxidation cycle as in practice the theoretical yield isn't attained - it's generally closer to ATP per NADH molecule produced, for each FADH 2 Molecule produced and this equates to 10 per cycle of the TCA [ citation needed ] (according to the P/O ratio ), broken down as follows:
*The amino acids arginine , methionine and phenylalanine are considered essential for reasons not directly related to lack of synthesis. Arginine is synthesized by mammalian cells but at a rate that is insufficient to meet the growth needs of the body and the majority that is synthesized is cleaved to form urea. Methionine is required in large amounts to produce cysteine if the latter amino acid is not adequately supplied in the diet. Similarly, phenylalanine is needed in large amounts to form tyrosine if the latter is not adequately supplied in the diet.