A-LevelBiologyNucleic acids and protein synthesisFeb/Mar 2021Paper 1 Q221 Mark
Which statements about complementary base pairing are correct? 1 Cytosine forms two hydrogen bonds with guanine. 2 Purines and pyrimidines are different sizes. 3 Adenine forms the same number of hydrogen bonds with thymine as it does with uracil. 4 The base pairs in a molecule of DNA are of equal length and equal width.
A1, 2 and 3
B1, 2 and 4
C1, 3 and 4
D2, 3 and 4
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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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