A-LevelBiologyNucleic acids and protein synthesisOct/Nov 2017Paper 1 Q231 Mark
Which statements concerning DNA and RNA are correct? 1 Adenine and guanine are bases that have a double ring structure; cytosine, thymine and uracil are bases with a single ring structure. 2 An adenine nucleotide from DNA is the same as an adenine nucleotide from RNA; DNA adenine pairs with thymine and RNA adenine pairs with uracil. 3 The base pairing that occurs in a double DNA helix and when RNA is synthesised during transcription is always according to the rule that a purine pairs with a pyrimidine. 4 The two polynucleotides on a DNA molecule run in opposite directions so that the double helix formed has two strands that are parallel to each other.
A1, 2 and 3
B1, 2 and 4
C1, 3 and 4
D2, 3 and 4
✓ 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...
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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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