Discussion Guide Chapter 9 Mader 10th edition 1. Biologists used to believe that interphase was a “resting period” during the life cycle of the cell. Why did this appear to be so? What is interphase now considered to be? Go to http://www.nobel.se/medicine/educational/2001/cellcycle.html 2. What is the G1/S checkpoint and where does it fit into the cell cycle? 3. What cell conditions are being monitored at the G1/S checkpoint? 4. What is the G2/M checkpoint and where does it fit into the cell cycle? 5. What cell conditions are being monitored at the G2/M checkpoint? 6. What is the spindle checkpoint and where does it fit into the cell cycle? 7. What cell conditions are being monitored at the spindle checkpoint? 8. Why is the regulation of the cell cycle critical to normal function in the multicellular organism? 9. For each of the following, takes notes about what type of molecule they are and their role in the cell cycle. a. Cdk’s b. Cyclins c. growth factors d. p53 10. Use the following terms to describe chromosomes in a cell. Haploid, diploid, histones, chromatin, centromere, chromatid 11. Label the following diagram with chromatid, centromere, kinetochore, sister chromatids 12. Mitosis is traditionally split into 4 main stages, prophase, metaphase, anaphase, and telophase. Explain how mitosis is really a continuous process. 12. How is cytokinesis in animal cells different from that in plant cells? 13. Colchicine is a poison that binds to tubulin and prevents its assembly into microtubules; cytochalasins are compounds that bind to the ends of actin filaments and prevent their elongation. What effects do you think these two substances would have on cell division in animal cells? 14. Compare and contrast reproductive cloning with therapeutic cloning. 15. What are 6 characteristics of cancer? 16. How do proto-oncogenes differ from tumor-suppressor genes in the mechanisms by which they lead to excessive cell proliferation and cancer? 17. How does a prokaryotic chromosome differ from a eukaryotic chromosome? 18. How does binary fission differ from mitosis?