chapter 18 key terms the cell division cycle

  1. anaphase
    stage of mitosis during which the two sets of chromosomes separate and move away from each other. composed of anaphase A (chromosomes move toward two spindle poles) and anaphase B (spindle poles move apart).
  2. anaphase promoting complex (APC)
    a protein complex that promotes the destruction of specific proteins, by catalyzing their ubiquitylation. it is a crucial component of the cell cycle control system.
  3. apoptosis
    normal, benign type of programmed cell death in which a cell shrinks, fragments its DNA, and alters its surface so as to activate the cell's phagocytosis by microphages.
  4. aster
    star-shaped system of microtubules emanating from a centrosome or from a pole of a mitotic spindle.
  5. Bcl2 family
    family of intracellular proteins that either promote or inhibit apoptosis by regulating the activation of caspases.
  6. bi-orientation
    the symmetrical alignment of sister chromatids on the mitotic spindle, such that one chromatid is attached to one spindle pole and the other chromatid to the opposite pole.
  7. caspase
    a family of proteases. members of the family are activated as part of the pathway leading to apoptosis.
  8. Cdk (cyclin-dependent protein kinase)
    protein kinase that has to be complexed with a cyclin protein in order to act. different Cdk-cyclin complexes trigger different steps in the cell-division cycle by phosphorylating specific target proteins.
  9. Cdk inhibitor protein
    protein that inhibits cyclin-Cdk complexes, primarily to inhibit progress though the G1 and S phases of the cell cycle.
  10. cell cycle
    reproductive cycle of the cell: the orderly sequence of events by which a cell duplicates its contents and divides into two.
  11. cell-cycle control system
    network of regulatory proteins that governs progression of a eukaryotic cell through the cell cycle.
  12. centrosome (cell center)
    centrally located organelle of animal cells that is the primary microtubule-organizing center and separates to form the two spindle poles during mitosis. in most animal cells it contains a pair of centrioles.
  13. centrosome cycle
    duplication of the centrosome (during interphase) and separation of the two new centrosomes (at the beginning of mitotsis), to form the poles of the mitotic spindle.
  14. checkpoint
    point in the eukaryotic cell-division cycle where progress through the cycle can be halted until conditions are suitable for the cell to proceed to the next stage.
  15. chromosome condensation
    process by which a chromosome becomes packed into a more compact structure prior to M phase of the cell cycle.
  16. cohesin
    protein complex that forms a ring that holds sister chromotids together after DNA has been replicated in the cell cycle.
  17. condensin
    protein complexes with a ring-like structure that help carry out chromosome condensation.
  18. cyclin
    protein that periodically rises and falls in concentration in step with the eukaryotic cell cycle. Cyclins activate specific protein kinases and thereby help control progression from one stage of the cell cycle to the next.
  19. cytokinesis
    division of the cell cytoplasm of a plant or animal cell into two, as distinct from the division of its nucleus (which is mitosis).
  20. G1-Cdk
    cyclin-dependent kinase whose activity drives the cell through G1 phase.
  21. G1 cyclin
  22. G1 phase
    Gap 1 phase of the eukaryotic cell cycle, between the end of cytokinesis and the start of DNA synthesis.
  23. G2 phase
    Gap 2 phase of the eukaryotic cell cycle, between the end of DNA synthesis and the beginning of mitosis.
  24. G1/S-Cdk
    cyclin-dependent kinase whose activity triggers entry into the S phase of the cell cycle.
  25. G1/S cyclin
  26. growth factor
    extracellular polypeptide signaling molecule that stimulates a cell to grow or prolifereate. examples are epidermal growth factor (EGF) and platelet-dervived growth factor (PDGF).
  27. interphase
    long period of the cell cycle between on mitosis and the next. includes G1 phase, S phase, and G2 phase.
  28. kinetochore
    complex protein-containing structure on a mitotic chromosome to which microtubules attach. The kinetochore forms on the part of the chromosome known as the centromere.
  29. M-Cdk
    active protein complex formed at the start of M phase of the cell cycle by an M-cyclin and the mitotic Cdk.
  30. M cyclin
    cyclin protein that binds to mitotic Cdk to form M-Cdk at the start of M phase of the cell cycle.
  31. M phase
    period of the eukayotic cell cycle during which the nucleus and cytoplasm divide.
  32. metaphase
    stage of mitosis at which chromosomes are firmly attached to the mitotic spindle at its equator but have not yet segregated toward opposite poles.
  33. mitogen
    an extracellular signal molecule that stimulates cell proliferation.
  34. mitosis
    division of the nucleus of a eukaryotic cell, whcih involved condensation of the DNA into visible, chromosomes.
  35. mitotic spindle
    array of microtubules and associated molecules that forms between the opposite poles of a eukaryotic cell during mitosis; during the separation of the duplicated chromosomes, the spindle serves to move the two chromosome sets apart.
  36. origin recognition complex (ORC)
    large protein complex that is bound to the DNA at the origins of replication in eukaryotic chromosomes thought the cell cycle.
  37. p53
    regulartory protein that responds to the presence of DNA damage, preventing the cell from entering S phase until the damage has been repaired.
  38. phragmoplast
    structure made of microtubules and membrane vesicles that forms in the equatorial region of a dividing plant cell and from which the membrane that divides the daughter cells will be made.
  39. programmed cell death
    see apoptosis
  40. prometaphase
    stage of mitosis that precedes metaphase.
  41. prophase
    first stage in mitosis during which the chromosomes are condensed but not yet attached to a mitotic spindle.
  42. S-Cdk
  43. S cyclin
  44. S phase
    period during a eukaryotic cell cycle in which DNA is synthesized.
  45. sister chromatid
    one copy of a chromosome (a chromotid) formed by DNA replication that is still joined at the centromere to the other copy, the pair of chromotids being known as sister chromotids.
  46. spindle pole
    one of two centrosomes in a cell undergoing mitosis. microtubules radiating from these centrosomes form the mitotic spindle.
  47. survival factor
    extracellular signaling molecule that must be present to prevent apoptosis.
  48. telophase
    final stage in mitosis in which the two sets of separated chromosomes decondense and become enclosed by nuclear envelopes.
Card Set
chapter 18 key terms the cell division cycle
key terms from ch 18