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Inserting one or two nucleotides changes the triplet reading frame, altering the message for:
AOnly the first amino acid
BOnly the last amino acid
CNo amino acid at all
DEvery subsequent amino acid
Answer & Solution
Correct answer: D. Every subsequent amino acid
1. The code is read in non-overlapping triplets from a fixed start.
2. Each amino acid is defined by a three-nucleotide triplet codon.
3. The insertion of one or two nucleotides completely changed the triplet reading frame.
4. That shift thereby altered the message for every subsequent amino acid.
5. An insertion of three nucleotides would instead preserve the frame.
_Source: OpenStax Biology 2e (CC BY 4.0), Ch 15 'Genes and Proteins', sections 15.1-15.5_
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