Missense mutation changing tyrosine to tryptophan Steps:

• Identify original DNA codon ATA (coding strand) transcribes to mRNA UAU, coding for tyrosine.
• Substituted DNA codon ACC transcribes to mRNA UGG, coding for tryptophan.
• This is a point mutation (substitution) altering the amino acid in the protein.
• Result is a missense mutation, not silent or nonsense, as it changes Tyr to Trp without creating a stop codon. Why C is correct:
• C (3 and 4) matches effects like amino acid change (missense) and potential protein function alteration, per genetic code definitions. Why the others are wrong:
• A includes 1 and 2 (e.g., no effect or silent mutation), but substitution changes the amino acid.
• B includes 1 (no effect), ignoring the codon change.
• D includes 2 (silent), but mRNA codons differ in meaning. Not enough information on exact statements 1–4.

Final answer: C