A-LevelBiologyNucleic acids and protein synthesisFeb/Mar 2023Paper 1 Q231 Mark
The PDx1 protein is found in a wide range of animal species where it is regarded as essential for normal metabolism. In sand rats, the gene coding for the PDx1 protein has a much lower proportion of A and T nucleotides than PDx1 genes from other animals. Finding the complete DNA sequence of the PDx1 gene in sand rats has been difficult. Sequencing involves splitting off nucleotides one at a time from single-stranded DNA. What could account for the difficulty in finding the DNA sequence of the PDx1 gene in sand rats? 1 The PDx1 gene is present in only a small proportion of nuclei. 2 The PDx1 gene is transcribed in only some cells. 3 The strength of the hydrogen bonding between the two strands of the PDx1 gene is unusually high.
A1, 2 and 3
B1 only
C2 only
D3 only
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The correct answer is D. This question tests the candidate's understanding of nucleic acids and protein synthesis within the Biologysyllabus. The examiner's mark scheme requires...
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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...
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