Stop codon — Science definition
An mRNA codon such as UAA that signals termination instead of adding another amino acid.
Where it is taught
- Protein Synthesis — DNA, Inheritance & Gene Expression, Life Science: Biology, Grade 10
Questions using stop codon
Problem 1
A coding sequence contains 300 mRNA bases, including one stop codon. How many amino acids does the resulting polypeptide contain?
Answer and explanation
99
300 / 3 = 100 codons, one of which is a stop and specifies no amino acid, leaving 99 amino acids.