A-LevelBiologyNucleic acids and protein synthesisMay/June 2022Paper 1 Q231 Mark
The table shows the DNA triplet codes for some amino acids. amino acid DNA triplet code amino acid DNA triplet code arginine GCA glycine CCA arginine GCC glycine CCG arginine GCG glycine CCT asparagine TTA lysine TTC asparagine TTG lysine TTT cysteine ACA proline GGA cysteine ACG proline GGC STOP ATC valine CAC The base sequence on the template DNA strand coding for part of a polypeptide is shown. CCA ACG GCG TTA TTC GCA Two mutations occur in this sequence during DNA replication. Which mutated template DNA strand would result in a shorter polypeptide?
ACCA ACA GCA TTA TTC GCA
BCCA ACG CCG TTA TTC GCC
CCCA ACG GCG TTG ATC GCA
DCCT ACG GCG TTA TTC GGA
✓ Correct Answer
The correct answer is C: CCA ACG GCG TTG ATC GCA
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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