1. Can you name each of the 20 amino acids abbreviated in the table?
[Hint: The answers appear in the window status bar at the bottom of the page when the mouse is over the abbreviation.]

2. Two of the 20 amino acids were not pictured in the first 15 questions. A click on the abbreviations for these amino acids will show their structures in the right hand frame.
A click on the other 18 will refer you to the question where they did appear.