1) Cell proliferation and Cell growth depend on extracellular signal molecules called growth factors and mitogens. What would happen if cell proliferated without the effects caused by these molecules?  Explain the mode of action that these molecules utilize, and what effects these mitogens and growth factors have on cells?  Specifically explain one growth factor and one mitogen and the cellular signaling they trigger within the cell, as well as the final result of that signaling.

2) Explain how cancers can arise even though we have cell cycle checkpoints that are meant to check the viability and readiness of the cell to divide. What are carcinogens and why and how might they effect the cell cycle in the transformation of normal cells to cancer cells.

3) What reasons might the human body have an apoptotic pathway which signals for cellular death in light of the fact that cells primary purposes are to survive and multiply.  Explain why and how apoptosis might be part of the normal daily repair of genetic damage, knicks , cuts, bruises and breaks in the human body.

4) Bacteria are microbes whose sole purpose is to survive and multiply. just like human cells, but explain why bacteria do not have apoptotic signaling pathways.  Would it be beneficial if these bacteria did have apoptotic pathways built into their cellular machinery?

5) For humans, explain what the "hayflick limit" is and why and how it is different from apoptosis?