Biology 9700 · AS & A Level · The microscope in cell studies

The microscope in cell studies — practice question

XNA is a nucleic acid produced in the laboratory. It is constructed from nucleotides in which one part has been substituted with chemical X. Chemical X is organic, but it does not occur naturally. The section of the molecule that carries the code is unchanged. Which part of a DNA or RNA nucleotide has been replaced by the organic chemical X?

  • Afive-carbon sugar
  • Bphosphate group
  • Cpurine base
  • Dpyrimidine base

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