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A-LevelBiologyNucleic acids and protein synthesis9700/12 · May/June 2023 · Q251 Mark

The DNA triplets of genes are translated as amino acids or stop signals during protein synthesis. The table shows some of these triplets. [Figure 25.1] What could be the effects of one substitution mutation in a triplet coding for tyrosine? 1 The triplet is translated as cysteine. 2 The triplet is translated as tryptophan. 3 The triplet is translated as tyrosine. 4 Translation stops at this triplet.

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A1, 2 and 3
B1, 2 and 4
C1, 3 and 4
D2, 3 and 4

✓ Correct answer

C: 1, 3 and 4

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Topic
Nucleic acids and protein synthesis, A-Level Biology (syllabus 9700). Multiple choice, 1 mark.
Source
A-Level Biology, May/June 2023 Paper 1 Variant 2, question 25.

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