Biology 9700 · AS & A Level · Replication and division of nuclei and cells

Replication and division of nuclei and cells — practice question

The statements refer to two genes and the proteins they produce, both of which may contribute to tumour development. • The protein encoded by the $PTEN$ gene stops cells from increasing in size and dividing too quickly. • The protein encoded by the $p53$ gene stops cells from moving on through the mitotic cell cycle when those cells contain damaged DNA. Which pair of mutations in these two genes in one individual is most likely to lead to tumour formation?

  • A$PTEN$: mutation present; $p53$: mutation present
  • B$PTEN$: no mutation; $p53$: mutation present
  • C$PTEN$: mutation present; $p53$: no mutation
  • D$PTEN$: no mutation; $p53$: no mutation

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