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Nonsense codons

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Nonsense codons are sequences of DNA that signal the termination of protein synthesis. They do not encode amino acids and cause translation to stop.

5 Must Know Facts For Your Next Test

  1. Nonsense codons are also known as stop codons.
  2. The three nonsense codons in the genetic code are UAA, UAG, and UGA.
  3. These codons do not correspond to any tRNA molecules.
  4. Nonsense codons are crucial for defining the end of mRNA translation.
  5. A mutation that introduces a premature nonsense codon can result in a truncated, nonfunctional protein.

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