Isaac Bashevis Singer

What do they know-all these scholars, all these philosophers, all the leaders of the world - about such as you? They have convinced themselves that man, the worst transgressor of all the species, is the crown of creation. All other creatures were created merely to provide him with food, pelts, to be tormented, exterminated. 

All Essential Amino Acids

An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized by the organism, and must be supplied in diet. 

The 9 amino acids humans cannot synthesize (F V T W M L I K H):

• phenylalanine
• valine
• threonine
• tryptophan
• methionine
• leucine
• isoleucine
• lysine
• histidine

Animal and plant proteins are made up of about 20 common amino acids.

Synthesis of 6 other amino acids - conditionally essential - can be limited under special conditions (R C G Q P Y): arginine, cysteine, glycine, glutamine, proline, and tyrosine.

Dispensable amino acids can be synthesized in the human body, 5 (A D N E S): alanine, aspartic acid, asparagine, glutamic acid and serine .