CAIE A Level Biology 9700 · Nucleic acids and protein synthesis
A student examines models of a deoxyribonucleotide (monomer of DNA) and an ATP molecule. Both contain the nitrogenous base adenine. The DNA nucleotide has deoxyribose and one phosphate group. ATP has ribose and three phosphate groups. Explain how these structural differences are related to the role of DNA nucleotides as building blocks of DNA and the role of ATP in providing energy for cellular processes, such as DNA replication.
6 marks, so the mark scheme is looking for about 6 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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