A point mutation changes the DNA codon CTT to CTC, but the amino acid in the protein is unchanged. Why?
Answer and explanation
Correct answer: A. The genetic code is degenerate
- Step 1: A silent mutation changes a base but not the amino acid.
- Step 2: This occurs because the genetic code is degenerate: several codons specify the same amino acid.
Answer
The genetic code is degenerate.
Why not the others: The genetic code is non-overlapping: non-overlapping does not explain why the amino acid is unchanged. Mutations never affect the base sequence of the exons: this mutation changed the base sequence. tRNA changes shape to correct the mutation: tRNA cannot correct mutations in DNA.
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