A point mutation changes the mRNA codon AAA (lysine) to AAG (lysine). Explain why this mutation is silent and describe how wobble pairing allows the same amino acid to be coded.
Answer
It is silent because both codons encode lysine; wobble pairing permits the same tRNA to recognize both codons.
The correct answer is It is silent because both codons encode lysine; wobble pairing permits the same tRNA to recognize both codons. — Thus the mutation does not affect the protein sequence.
Step-by-step solution
- Identify the two codons: AAA and AAG.
- Look up the genetic code: both codons translate to lysine.
- Since the amino acid does not change, the mutation is silent.
- Wobble pairing refers to the flexibility at the third base of a codon.
- Because the third base varies (A vs G), the same tRNA with anticodon UUU can pair with both codons.
- Thus the mutation does not affect the protein sequence.
Common mistake: Assuming the mutation changes the amino acid
Concept tested: Silent mutation & wobble pairing
Published · How this solution was prepared and checked
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