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

The microscope in cell studies — practice question

The four nucleotides, A, B, C and D, each contain three phosphate groups, one nitrogenous base and one pentose sugar. The table shows the features of the base and sugar parts before they are combined to make each nucleotide. Which nucleotide can bind to an adenine base during DNA replication?

  • Adouble ring nitrogenous base; carbon:oxygen ratio in pentose sugar = $1:1$
  • Bdouble ring nitrogenous base; carbon:oxygen ratio in pentose sugar = $5:4$
  • Csingle ring nitrogenous base; carbon:oxygen ratio in pentose sugar = $1:1$
  • Dsingle ring nitrogenous base; carbon:oxygen ratio in pentose sugar = $5:4$

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