Can you name the one-letter code of all 20 standard amino acids? Type the letter used for each amino acid in protein sequences, then read why it got that letter and a key fact about it. Some codes are simply first letters, while others follow less obvious rules. Great practice for biochemistry, biology and molecular biology students.

Do you know the three-letter abbreviations of all 20 standard amino acids? Type the code used for each one, then find out where it comes from: most codes are simply the first three letters of the name, but a few break the rule. Each answer also explains the origin of the amino acid’s name. Useful practice for biochemistry, biology and molecular biology students.