The chemical structure of uracil.
Uracil, abbreviated U, is a pyrimidine base. It appears blue in EteRNA. Uracil pairs with adenine and guanine. Uracil is unique to RNA, and does not appear in DNA, being replaced by thymine.
Uracil (in Blue) bonding with both Adenine (in Yellow) and Guanine (in Red) with a Guanine boost inside the loop.