🧬ap biology review

Uracil (U)

Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 examWritten by the Fiveable Content Team • Last updated September 2025

Definition

Uracil is a nitrogenous base found only in RNA. It replaces thymine from DNA and pairs with adenine during transcription.

"Uracil (U)" also found in: