Cell bio 406 lecture 10

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Cell bio 406 lecture 10
2013-08-13 20:20:41
Cellular Biology 406 Cell cycle cell division

cell cycles and division
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  1. What is the cell cycle?
    series of events leading to cell division, composed of growth, synthesis, and mitosis.
  2. What is G1 of the cell cycle?
    cellular contents excluding chromosomes are duplicated?
  3. What is the S phase?
    each of the 46 chromosomes are duplicated.
  4. What is the G2 phase?
    Cell double checks the duplicated chromosomes for error and makes any necessary repairs.
  5. What is G0 phase?
    cell cycle arrest
  6. How is mitosis characterized?
    by location and behavior of chromosomes.
  7. How is mitosis separated?
    karyokinesis and cytokinesis.
  8. What is the most important kinase in mitosis?
    cyclin B/CDK1 complex- the master mitotic regulator
  9. When are chromosomes visible?
    during mitosis NOT INTERPHASE
  10. What mediates chromatin condensation?
    condensin- a complex of several proteins that bind and encircle DNA forming loops and coils
  11. What aids in chromosome separation?
    the mitotic spindle
  12. What are spindles?
    bipolar arrays of microtubules composed of tubulin
  13. What nucleates teh growth of the spindle microtubules?
  14. Where do spindles attach?
    at the chromosomes kinetochores in the most contricted region of the chromosome (the centromere)
  15. Where does the centrosome nucleate?
    the - end
  16. Where does the microtubule attach?
    the + end attaches to the kinetochore on the centromere
  17. What are the 5 phases of mitosis?
    prometaphase, metaphase, anaphase, and telophase
  18. What occurs during prophase?
    chromosomes coil and supercoil
  19. What happens during prometaphase?
    nuclear envelope breaks down and kinetochore microtubules appear
  20. What happens during metaphase?
    centrosomes align
  21. What happens during anaphase?
    sister chromatids separate
  22. What happends during telophase?
    daughter chromosomes reach poles and nuclear envelop/nucleoli reform
  23. what is endoreduplication?
    replication of hte genome without cell division or cytokinesis
  24. What are the types of endoreduplication?
    endocycle and endomitosis.
  25. Why is endoreduplication necessary?
    the need to increase cell size or if that cell needs a lot of genetic information in order to respond to stress signals.
  26. What happens if cell cycle progression is defective?
    p53 is activated leading to cell cycle arrest, DNA repair, apoptosis, or senescence
  27. What is myc?
    a transcription factor downstream of RTKs that promotes proliferation when activated and is involved in disease and development.
  28. What is the G1 checkpoint?
    is environment favorable?
  29. What is G2 checkpoint?
    is all DNA replicated and is environment favorable
  30. What is M checkpoint?
    are all chromosomes attached to the spindle
  31. How do checkpoints generally operate?
    through negative intracellular signals
  32. What happens if a checkpoint is inactive?
    Cell cycle progesses even with errors
  33. What are CDKs and what do they do?
    Cyclin-dependent kinases regulate cell cycle.
  34. How are CDKs activated?
    when complexed with a cyclin protein
  35. How does CDK control the cell cycle?
    associating with different cyclins  to trigger different events
  36. What terminates CDK function?
    CDK degradation
  37. What do G1 and S cyclins do?
    bind CDKs at the end of G1 and commit the cell to DNA replication.
  38. What do S-cyclins do?
    bind CDKs during S phase and are required for initation of DNA replication.
  39. What do M cyclins do?
    promote the events of mitosis
  40. How are CDK-cyclin complexes regulated?
    phosphorylation, inhibitory proteins, proteolysis, ad subcellular localization
  41. What does CAK do?
    phosphorylates CDK1 to activate CDK1-CyclinB complex
  42. What does Wee1 do?
    phosphorylates CDK1 to inactivate the CDK1-Cyclin B complex at G2.
  43. What does CDC25 do?
    Reverse Wee1 phosphorylation to allow G2 to M transition.