Amino acid contributions to growth. The results of adding equivalent quantities of each amino acid to the media are shown here. Red bars represent amino acids that are reported essential in the literature, and green bars are amino acids that are not. Arginine is present in all cases and is the baseline against which the rest of the values are normalized. On average, adding an essential amino acid to the media allows better growth than does adding a non-essential amino acid. E stands for average essential amino acid, and NE stands for average non-essential amino acid. Two amino acids do not have transporters in the genome annotation and are not included here for that reason.