You can satisfy the letters of recommendation requirement by submitting one of the following options:
Option 1:
One letter of reference from the Pre-Professional Advisory Committee of your college or university
OR
Option 2:
At least two letters of reference from professors who can provide a detailed evaluation of your performance in appropriate university science courses, e.g. biology lecture/lab, chemistry lecture/lab, organic chemistry lecture/lab, biochemistry lecture/lab, etc. (Please note that a letter of reference from a research mentor or research supervisor cannot meet this requirement. However, it will serve as a supplement in your admissions application.)