A-LevelBiologyNucleic acids and protein synthesisOct/Nov 2020Paper 1 Q221 Mark
The DNA sequence CCAAGAAGTCGACAAACA is translated to synthesise the amino acid chain gly-ser-ser-ala-val-cys. As a result of a mutation, the sequence length of the amino acid chain is shortened from six to two amino acids. A stop codon in mRNA is UGA. Which base in the DNA sequence was changed by the mutation?
AA
BC
CG
DT
✓ Correct Answer
The correct answer is C. This question tests the candidate's understanding of nucleic acids and protein synthesis within the Biologysyllabus. The examiner's mark scheme requires...
📋 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...
🔒
Unlock the Examiner's Answer
Sign up for free to reveal the correct answer, the official mark scheme breakdown, and the examiner trap analysis for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep