Molecular basis of mutations — A/L Biology

How do I practise Molecular basis of mutations?

1 question with a worked solution

1. What type of point mutation occurs when a single nucleotide substitution changes a codon specifying an amino acid into a premature stop codon?
   1. A) Nonsense mutation
   2. B) Frameshift mutation
   3. C) Silent mutation
   4. D) Missense mutation
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   Correct answer: A) Nonsense mutation

   A nonsense mutation is a point mutation that converts a sense codon encoding an amino acid into a premature stop codon (UAA, UAG, or UGA), resulting in a truncated, non-functional polypeptide.

   Show worked solution

   Step 1: Review types of base-pair substitutions: - Silent: no change in amino acid due to degeneracy. - Missense: substitutes one amino acid for another. - Nonsense: replaces an amino acid codon with a termination (stop) codon. Step 2: Conversion to stop codon = Nonsense mutation. Answer: Nonsense mutation.
   Modelled on: the A/L Biology examination pattern

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Where does Molecular basis of mutations fit in the syllabus?

Year 1 · Term 2