Biology 9700 · AS & A Level · Structure of nucleic acids and replication of DNA

Structure of nucleic acids and replication of DNA — practice question

(a)[1]

Name the phase of the mitotic cell cycle in which DNA replication happens.

(b(i))[1]

Fig. 5.1 gives details of DNA replication. Name the bonds indicated by the dashed lines on Fig. 5.1.

(b(ii))[1]

Identify the nitrogenous bases labelled M and O.

(c)[2]

Explain why DNA replication is referred to as semi-conservative.

(d)[2]

The enzyme that catalyses DNA replication scans for mistakes during the process and repairs them. This ensures that the cells formed in mitosis are genetically identical. Explain why it is necessary to check for errors and correct them.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: S phase / synthesis phase / interphase

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