The diаgrаm belоw shоws the pаthway by which mitоgens reactivate the cell cycle in senescent cells. (Description of pathway: A mitogen binds its receptor → activates Ras → activates MAP kinase → increases transcription of Myc → Myc promotes transcription of Cyclin D → Cyclin D binds and activates G1-Cdk → activated G1-Cdk inactivates Rb protein → inactive Rb releases and allows activation of E2F → E2F promotes transcription of S-phase genes → S-Cdk is activated → DNA synthesis begins.) Question: A mutation occurs that causes Rb protein to be permanently inactive in a cell, even in the absence of a mitogen signal. What would you expect to happen in this cell?