Biol 309 Test Question Bank Cell CycleMultiple Choice1. The role of ‘cyclin’ in the regulation of the cell cycle would be best compared to:A. a digital watch that produces a precisely timed signal every few microseconds.B. a row of dominoes, that all fall sequentially after the first one is flipped.C. a light switch that alternates between on and off states.D. the accumulation of sand in an hourglass.2. Which one of the following statements best describes the mechanism by which the "cell cyclecontrol system" regulates events of the cell cycle?A. Ca++ and cAMP are leased into the nucleus at particular times.B. Protein activity is regulated through phosphorylation and dephosphorylation.C. Specific hormones signal when it’s time to move to each stage of the cell cycle.D. Changes in membrane potential signal progress of the cell cycle.3. A cell cycle "checkpoint" would be best described as:A. a site in the cytoplasm where proteins are inspected for mutations.B. either G1, S, G2, prophase, metaphase, anaphase or telophase.C. specific stages where further progress of the cell cycle can be halted.D. any step where the cell cycle is blocked by a mutated protein.4. The figure to the right shows the changes in the level of a cyclin andactivity of cyclin-Cdk during the cell cycle. Note how the level of cyclinincreases slowly & steadily, whereas the activity of the cyclin-Cdk appearsquite suddenly. How would we best explain the rapid activation ofcyclin-Cdk?A. Cyclin-Cdk gene expression leads to rapid protein synthesis.B. All cyclin-Cdk is activated when it exists the nucleus.C. Ubiquination leads to proteolytic activation of the cyclin-Cdk.D. A positive feedback loop causes its rapid activation.5. Which of the following statements correctly describes p53?A. It is a membrane receptor that binds to a cell growth hormone.B. Cell division stops until p53 binds to DNA and repairs the damage.C. p53 is an example of an oncogene, and its expression causes uncontrolled cell division.D. activation of p53 leads to inhibition of the S-phase cyclin-CDK complex.6. All of the following statements correctly describe M-Cdk, EXCEPT:A. M-Cdk causes the cell to enter S phase and begin DNA replication.B. M-Cdk has two subunits, a protein kinase and a cyclin-type protein.C. M-Cdk only becomes active during M-phase.D. M-Cdk triggers many events by phosphorylating other proteins.Biol 309 Question Bank Cell CyclePage 17. The figure to the right shows that injection of M-phasecytoplasm into an oocyte triggers the cell to enter mitosis.What would be the expected effect on cell division ifcytoplasm from a G2-phase cell were injected into an M-phase cell?A. DNA replication would begin again.B. activation of all cyclin-CDK complex in the cell.C. it should have essentially no effect.D. mitosis will immediately stop.8. Which one of the following statements best describes the relationship between tumor suppressorproteins (TSP) and cancer?A. TSPs usually become mutated as a late event during cancer development.B. When activated, TSPs will cause uncontrolled cell division.C. Mutation of a TSP predisposes a cell to formation of oncogenes.D. Mutation to a TSP will cause a cell to undergo apoptosis.9. Certain cell surface molecules of bacteria can trigger cells of the immune system to abnormally begin to divide, sometimes leading to severe symptoms. This type of molecule would be best described as a:A. growth factor C. mitogenB. survival signal D. hormone10. Apoptosis involves all of the following events, EXCEPT:A. phagocytosis by macrophages.B. fragmentation of DNA.C. triggering of inflammation.D. formation of small membrane-bound vesicles.11. Which of these types of proteins are most responsible for assuring that cells do not replicate ifthere is DNA damage?A. cyclins C. protooncogenes proteinsB. tumor suppressor proteins D. inactivating phosphatases12. Each of the following events is likely to trigger cell apoptosis, EXCEPT:A. release of mitochondrial proteins into the cytosol.B. binding of Fas/FasL proteins on the cell surface.C. mutations that inhibit the activity of P53.D. unrepairable DNA damage.True or False1. Many tumor suppressor genes are involved in the detection and repair of DNA damage.2. Protein kinases are proteins that add phosphates to other proteins.3. Cyclins are kinases.Biol 309 Question Bank Cell CyclePage 24. Cyclins are targeted for destruction through ubiquination.5. A gene encoding a DNA repair enzyme would be an example of a protooncogene.6. S-phase Cdk activates DNA synthesis at replication origins, and its immediate destruction is whatprevents subsequent reactivation.7. Activation of caspase-type proteases is the first event triggering mitosis.8. Necrosis is the end-result of the systematic self-destruction of a cell.9. Many genes involved in check-point control of the cell-cycle would be classified as tumor-suppressor genes.10. Once mitosis begins, checkpoint control does not occur until the cell reenters G1.11. Proteases in the caspase family are responsible for the destruction of cyclin-Cdk.12. Different cyclin-Cdks are responsible for triggering different stages of the cell cycle.13. Mitogens are substances that trigger apoptosis.Matching1. Stage of cell cycle Cellular event or process__M A. cell metabolism prepares for mitosis__S B. ribosome and organelles increasing in number__G0 C. cell is not actively dividing__G1 D. histone synthesis is in high gear__G2 E. microtubule organizing center has been replicated2. Protein function__ cyclin A. phosphorylates target proteins__ cdk B. remove a phosphate from cyclin-Cdk__ cyclin-cdk complex C. triggers destruction of cyclin-Cdk __ activating phosphatase D. is the kinase in activated cyclin-CdkE. ubiquination leads to its proteolysisFill-in etc1. The detection of _________________ causes activation of p53. When activated, p53 triggers transcription of the protein called ___________, which itself acts to inhibit _______________.2. Uncontrolled rupturing of a cell is called ______________________, whereas controlled destruction of the cell into membrane-bound fragments is called ___________________________. The latter process is mediated by activation of a cascade of proteases called ___________________. Biol 309 Question Bank Cell CyclePage 33. _________________ are proteins that accumulate during the cell cycle and bind to