Due to the degenerate nature of the genetic code, not all base substitutions cause a change in the amino acid sequence
The genetic code is degenerate — multiple codons can code for the same amino acid. So swapping one DNA base for another sometimes makes no difference to the protein produced.
Real World
The amino acid leucine is coded for by six different codons (UUA, UUG, CUU, CUC, CUA, CUG). A mutation changing UUA to UUG still produces leucine, so the resulting protein is completely unaffected — a silent mutation.
Exam Focus
Always state whether the amino acid changes and then explain the consequence for protein shape and function.
Evaluation Scaffold
A four-step framework for high-quality evaluation. Use this for 'assess', 'evaluate', and 'to what extent' questions.
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