A tumor cell with a mutation in Rb can dividein the absence of extracellular signals.
A. If the Rb mutation is responsible for the increased celldivision, is it likely that Rb is always active oralways inactive? Explain your reasoning.
B. Which of the following molecules would be likely toblock division of these tumor cells? Select allthat would block division in cells with this Rbmutation.
      a. An inhibitor of RasGEF
  b. A MAPK inhibitor
      c. An inhibitor of the G1checkpoint Cdk
  d. An inhibitor of E2F (transcription factorregulated by Rb)
  e. An inhibitor of DNA polymerase
C. Explain why the choice/one choice in part B wouldblock division of cells expressing this Rbmutant.
D. Explain why one of the choices in part B that you did NOTselect would NOT block cell division in cell expressingthis Rb mutant.
