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Flashcards

The Cell Cycle

Tamara Johnson Advanced Cell Biology English 275 cards

1. Cell Growth and chromosome duplication 2. Chromosome segregation 3. Cell Division

Cards in this deck (275)

  1. 1What is an ordered series of events that ensures the duplication of cellular contents including organelles and genomic DNA, segregation of the duplicated genetic material, and finally cell division?The cell cycle
  2. 2—1. Cell Growth and chromosome duplication
    2. Chromosome segregation
    3. Cell Division    1. Cell Growth and chromosome duplication 2. Chromosome segregation 3. Cell Division
  3. 3What are the 4 phases of the eukaryotic cell cycle (in order)?1. G1
    2. S
    3. G2
    4. M    What are the 4 phases of the eukaryotic cell cycle (in order)?
  4. 4What phases are these? 1. It is time that allows cells to grow and double their mass of proteins and organelles 2. It allows the cell time to monitor both the internal and external environment 3. It allows time for the cell to determine whether or not conditions are suitable to enter S or M phases of the cell cycleGap phases (G1 and G2)
  5. 5Under what conditions will a cell will delay its progression through G1?Unfavorable
  6. 6Cells may even exit G1 to enter a specialized state called G0 What will happen to the cells in the G0?The cells are in a resting state and they can stay there until conditions become more favorable
  7. 7The G1 stage of the cell cycle contains a commitment point which has other names. What are the other names?Restriction point or "start"
  8. 8If conditions are favorable, cells pass "start" in the G1 cycle and are committed to enter what phase?S phase
  9. 9"Start" is the "point of no return", if a cell goes past this point, it must enter what? It cannot wait where?S phase, it can not 'wait' in G1
  10. 10Often G1, S and G2 phases are referred to as what?Interphase
  11. 11How much of a cell's lifetime can be spent in interphase?95% 
  12. 12The most basic function of the cell cycle is duplication and segregation of chromosomal DNA which occurs during what phases?S phase and M phase
  13. 13What happens during the S phase?Chromosome duplication (S for DNA Synthesis)
  14. 14What is the main event in the M phase?Mitosis (M for Mitosis)
  15. 15What two events happen in the M phase?1. Nuclear division (duplicated chromosome are segregation into two nuclei)
    2. Cytoplasmic division (the cell divides into two)
  16. 16What is made up of 5 distinct events that describe the progressive changes in the status of the DNA, the nucleus, the mitotic spindle, and the cell?Mitosis
  17. 17What is happening in the cell cycle at 1, 2 and 3?1. Chromosome duplication
    2. Mitosis
    3. Cytokinesis    What is happening in the cell cycle at 1, 2 and 3?
  18. 18What are the five phases of mitosis?1. Prophase
    2. Prometaphase
    3. Metaphase
    4. Anaphase
    5. Telophase    What are the five phases of mitosis?
  19. 19Significant changes in the biochemical state of the cells occurs when a cell progresses between what two phases?Metaphase to anaphase
  20. 20A cell can pause while in metaphase, but if it passes through the 'metaphase to anaphase' transition, what must happen to the cell?The cell must continue through mitosis, undergo cytokinesis and enter interphase
  21. 21What is this phase of mitosis? 1. The first stage of mitosis 2. Chromosomal DNA content is duplicated 3. Replicated chromosomes become condensed 4. Centrosome has duplicated and the mitotic spindle begins to assembleProphaseWhat is this phase of mitosis? 1. The first stage of mitosis 2. Chromosomal DNA content is duplicated 3. Replicated chromosomes become co...
  22. 22During prophase, replicated chromosomes become condensed into pairs of rigid compact structures called what?Sister chromatids
  23. 23During prophase, does the nuclear envelope remain intact or disintegrates?Remains intact
  24. 24Chromatid pairs are linked together along their length by protein complexes called what?Cohesin
  25. 25What is this phase of mitosis? 1. The nuclear envelope starts to breakdown 2. The condensed chromosomes attach to spindle microtubules via their kinetochoresPrometaphaseWhat is this phase of mitosis? 1. The nuclear envelope starts to breakdown 2. The condensed chromosomes attach to spindle microtubules vi...
  26. 26What are protein structures (A) located at the centromere region of each chromosome?KinetochoresWhat are protein structures (A) located at the centromere region of each chromosome?
  27. 27What phase of mitosis is this? 1. The chromosomes align at the equator of the spindle 2. Attachment of each sister chromatid to microtubules from opposing centrosomes to form bipolar attachmentsMetaphaseWhat phase of mitosis is this? 1. The chromosomes align at the equator of the spindle 2. Attachment of each sister chromatid to microtubu...
  28. 28What phase of mitosis is this? 1. The cohesion between the two sister chromatids is dissolved 2. The chromatids separate to form two daughter chromosomes 3. Each daughter chromosome moves towards the spindle poleAnaphaseWhat phase of mitosis is this? 1. The cohesion between the two sister chromatids is dissolved 2. The chromatids separate to form two daug...
  29. 29What facilitates each daughter chromosome moving toward the spindle pole?It is facilitated by kinetochore microtubule shortening and the elongation of spindle microtubules
  30. 30What phase of mitosis is this? 1. The two sets of daughter chromosomes reach the spindle poles 2. DNA decondenses 3. The nuclear envelope reassembles around each set of DNATelophaseWhat phase of mitosis is this? 1. The two sets of daughter chromosomes reach the spindle poles 2. DNA decondenses 3. The nuclear envelope...
  31. 31What begins to form during telophase that sets up division of the cellular material during cytokinesis?Contractile ring
  32. 32What phase is this? 1. The cytoplasm is divided into 2 parts by the contractile ring which creates two daughter cells each with one nucleus. 2. The interphase microtubule array reformsCytokinesisWhat phase is this? 1. The cytoplasm is divided into 2 parts by the contractile ring which creates two daughter cells each with one nucle...
  33. 33What is a highly controlled event operated by multiple cellular sensors that monitor the status of the cell?The cell cycle
  34. 34Accuracy and reliability of progression through the cell cycle is dependent on what 3 factors?1. Switches that control progression are binary (either on or off) and are nonreversible
    2. The system controlling cell cycle progression have backup mechanisms that allow the system to work even if some of the components fail
    The control system can be modified for specific cell types or intra- or extracellular signals
  35. 35What are the three major regulatory transitions, or checkpoints, in the eukaryotic cell cycle?1. The 'start' point
    2. G2 to M transition checkpoint
    3. Metaphase to anaphase transition checkpoin
  36. 36What will happen at the Start checkpoint (1) if the environment is favorable for cell division?
    Passage through the start checkpoint commits the
    cell to DNA duplication and entry into the cell cycle    What will happen at the Start checkpoint (1) if the environment is favorable for cell division?
  37. 37What will happen at the G2/M checkpoint (2), if all DNA is replicated and the environment is favorable for cell division?Cell will enter mitosisWhat will happen at the G2/M checkpoint (2), if all DNA is replicated and the environment is favorable for cell division?
  38. 38What will happen at the metaphase-to-anaphase checkpoint (3) if all chromosomes are attached to the spindle?Passage through this checkpoint ensures sister chromatid separation and cytokinesis
    (It will trigger anaphase and proceed to cytokinesis)    What will happen at the metaphase-to-anaphase checkpoint (3) if all chromosomes are attached to the spindle?
  39. 39The cell monitors the situation inside and outside of the cell at each of these checkoints and if a problem is detected, what will happen?The cell will halt progression
  40. 40If a problem in DNA replication is detected, where will the cell halt its progression until the problem is fixedThe G2/M checkoint
  41. 41If conditions are not ideal for cell proliferation, what will be activated preventing cell cycle entry?The "start" checkpoint
  42. 42Central to cell cycle progression are a family of protein kinases called what?"cyclin-dependent kinases" or CDKs
  43. 43Does the activity of cyclin-dependent kinases (CDKs) rise and fall or remain steady as the cell moves through the cell cycle?Rise and fall
  44. 44The cyclic nature of cyclin-dependent kinases (CDKs) leads to changes in the phosphorylation status of proteins that regulate what?The major events of the cell cycle
  45. 45The most important regulator of cylin-dependent kinases (CDK) activity are what proteins?Cyclin proteins
  46. 46Cyclins are essential for Cdk kinase activity, in their absence, Cdks are what?Inactive
  47. 47Cyclin dependent kinase and its bound cyclin are key to controlling what?The cell cycle
  48. 48What is X?CyclinWhat is X?
  49. 49Cyclin proteins undergo rounds of what across the cell cycle?Synthesis and degradation
  50. 50Do the levels of Cdk proteins remain constant or change?Remain constant
  51. 51It is the changes in protein levels of a protein that result in changes in Cdk activity which lead to the changes that accompany cell cycle progression. What is the protein?Cyclin
  52. 52What are the 4 classes of cyclins?1. G1/S
    2. S
    3. M
    4. G1
  53. 53What cyclin activates Cdk in late G1 triggering passage though the start checkpoint and entry into the cell cycle?G1/S
  54. 54What cyclin stimulates chromosome duplication and early mitotic events?S
  55. 55What cyclin triggers entry into mitosis. Functions at the G2/M transition?M
  56. 56What cyclin controls the activity of the G1/S cyclins?G1
  57. 57What happens to the G1/S cyclin level when cells enter S phase?Drop
  58. 58M cyclins activate Cdks for passage through what checkpoint?The G2/M checkpoint
  59. 59What kind of organism is this? There is only one Cdk protein which changes cyclin partners at different stages of the cell cycleYeast
  60. 60What kind of organsim has 4 different Cdks that interact with different cyclins?Vertebrates
  61. 61The binding of different cyclin proteins to different Cdks are responsible for what?1. Activating the Cdk
    2. Helping to determine the target proteins of the
    Cdk-cyclin complex
  62. 62Each Cdk-cyclin pair phosphorylates different protein substrates inducing what?Different downstream results at different times
  63. 63Full Cdk activation requires cyclin binding and Cdk phosphorylation by a separate kinase called what?"Cdk activating kinase" or CAKFull Cdk activation requires cyclin binding and Cdk phosphorylation by a separate kinase called what?
  64. 64In its inactive state the active site of Cdk is blocked by a portion of the Cdk protein itself called what?The T loop
  65. 65When bound to cyclin, Cdk is in a partially active state due to what?The movement of the T-loop away from the Cdk active site
  66. 66Full activation of the Cdk-cyclin complex is accomplished how? By what?Cdk phosphorylation by a Cdk-activating kinase
  67. 67Phosphorylation occurs on what in the T-loop which triggers a conformational change in Cdk resulting in an increased ability to recognize substates?A threonine
  68. 68Is (A) fully active, partially active or inactive?InactiveIs (A) fully active, partially active or inactive?
  69. 69Is (B) fully active, partially active or inactive?Partially activeIs (B) fully active, partially active or inactive?
  70. 70Is (C) fully active, partially active or inactive?Fully activeIs (C) fully active, partially active or inactive?
  71. 71What is the primary mode of regulating Cdk activity?Cdk association with various cyclins
  72. 72What are two mechanisms that act at distinct stages of the cell cycle to 'fine tune' Cdk activity?1. Wee1
    2. Cdc25    What are two mechanisms that act at distinct stages of the cell cycle to 'fine tune' Cdk activity?
  73. 73A pair of amino acids located above the Cdk active site are phosphorylated by the Wee1 kinase. Wee1 phosphorylation turns off what?The Cdk-cyclin complex
  74. 74The inhibitory phosphorylation of Wee1 can be removed by what? What is the result?Cdc25 phosphatase reactivating Cdk
  75. 75The Wee1 kinase was identified in a mutant screen for yeast that produced what kind of cells?Small sized cells
  76. 76Wee is Scottish for what?Small
  77. 77Which one is active(A or B)?AWhich one is active(A or B)?
  78. 78Which one is inactive(A or B)?BWhich one is inactive(A or B)?
  79. 79Besides Wee1 kinase, what is another mechanism of Cdk-cyclin inhibition?Association with a set of proteins called Cdk inhibitor proteins, or CKIs
  80. 80A CKI (human p27 protein) binds to both Cdk and cyclin promoting what? Inhibiting what?A distortion of the CDK active site inhibiting Cdk activity
  81. 81CKIs are primarily used early in the cell cycle to control the activities of what?G1/S and S-Cdks
  82. 82Which one (A or B) is the inactive cyclin-Cdk complex?BWhich one (A or B) is the inactive cyclin-Cdk complex?
  83. 83Which one (A or B) is the active cyclin-Cdk complex?AWhich one (A or B) is the active cyclin-Cdk complex?
  84. 84Changes Cdk-cyclin phosphorylation drives progression through what two checkpoint?The Start and the G2/M checkpoints
  85. 85Progression through the metaphase to anaphase checkpoint is regulated by ubiquitin mediated protein degradation which is carried out by what?The anaphase promoting complex (APC) or the cyclosomeProgression through the metaphase to anaphase checkpoint is regulated by ubiquitin mediated protein degradation which is carried out by w...
  86. 86What is a ubiquitin ligase responsible for transferring multiple copies of a small protein, ubiquitin, to target proteins?The APCWhat is a ubiquitin ligase responsible for transferring multiple copies of a small protein, ubiquitin, to target proteins?
  87. 87When the ubiquitin chain reaches a certain length, the target protein is subjected to degradation by what?The proteasome
  88. 88The APC triggers the metaphase-anaphase transition by targeting what 2 major classes of proteins for degradation?Securin and the S- and M-cyclins
  89. 89What is required for maintaining sister chromatid pair cohesion during early mitosis?Securin
  90. 90APC targeted degradation of securin activates a protease that triggers what?The segregation of sister chromatids
  91. 91APC-mediated destruction of the S and M cyclins will inactivate what?Most CDKs in the cell
  92. 92APC-mediated destruction of the S and M cyclins will inactivate most CDKs in the cell. As a result, proteins phosphorylated by Cdks from S-phase to early mitosis will become what? by what?Dephosphorylated by cellular phosphatases
  93. 93Dephosphorylation of these target proteins is required for completion of what phase of mitosis?M phase
  94. 94The APC remains active into G1. When is G1 turned off? Why? To promote what?It is turned off in late G1 allowing cyclin accumulation to promote the start of the next cell cycle
  95. 95Activation of the ubiquitin ligase activity of the APC requires that it associate with what two activating proteins?Cdc20 or Cdh1
  96. 96APC associates with Cdc20p during what phase of mitosis?Anaphase
  97. 97APC associates with Cdh1 during what phases of mitosis?From late mitosis through early G1
  98. 98Association with different activating proteins, at different stages of the cell cycle, allows for what?APC recognition of different target substrates at different times
  99. 99Besides APC, what is another ubiquitin ligase that is important for regulating progression through the cell cycle?SCF (Skp, cullin, F-box containing complex)Besides APC, what is another ubiquitin ligase that is important for regulating progression through the cell cycle?
  100. 100The SCF ubiquitin ligase targets CKI proteins in late G1 for what? Triggering activation of what?Degradation triggering activation of S-Cdks and DNA replicationThe SCF ubiquitin ligase targets CKI proteins in late G1 for what? Triggering activation of what?
  101. 101What is a large multiprotein complex whose activity is dependent on its association with accessory proteins?SCF (Skp, cullin, F-box containing complex)What is a large multiprotein complex whose activity is dependent on its association with accessory proteins?
  102. 102Accessory proteins, called what, are involved in the recognition of specific phosphorylated target proteins?F-box proteinsAccessory proteins, called what, are involved in the recognition of specific phosphorylated target proteins?
  103. 103Are SCF levels constant or variable across the cell cycle?Constant
  104. 104It is the phosphorylation status of its target proteins that direct F-box recognition for SCF mediated what?Ubiquitination and degradation
  105. 105If conditions are favorable for cell division, internal and external signals trigger the activation of what?G1-Cdk
  106. 106If conditions are favorable for cell division, internal and external signals trigger the activation of G1-Cdk which activates expression of what two kinds of cyclins?G1/S and S phase cyclins
  107. 107Once bound to Cdk, the G1/S cyclin drives progression through what checkpoint?Start checkpoint
  108. 108S-Cdk activity intitates what?Chromosome duplication in S phase and some of the early events of mitosis
  109. 109If during this time the cell detects DNA damage, activity of G1/S-Cdk and SCdk are what? Preventing what?Blocked preventing passage through 'start' or entry into S phase
  110. 110Undamaged cells will progress through S phase triggering what activity?M-CDK activity
  111. 111Undamaged cells will progress through S phase triggering M-CDK activity promoting passage through the G2/M checkpoint leading to sister chromatid alignment at what plate?The metaphase plate
  112. 112M cyclin-Cdk complex ensures DNA replication occurs how many times during the cell cycle by blocking DNA re-replication (unreplicated DNA or the persistance of DNA damage will block M-Cdk activity)?Only once
  113. 113For cells that enter mitosis, APC activation by Cdc20 triggers destruction of securin and cyclins enabling what?Sister chromatid separation and the completion of mitosis
  114. 114A cell must ensure that DNA duplication occurs one time per cell cycle and that duplication is accurate to prevent what?Mutations
  115. 115What play a role in ensuring that replication occurs one time for each round of cell division?Cdk-cyclins
  116. 116Every chromosome contains what (shown in blue) which defines the start sites for DNA replication'Origins of replication'Every chromosome contains what (shown in blue) which defines the start sites for DNA replication
  117. 117In late mitosis of the previous cell cycle into early G1 of the new cell cycle, what assembles at these origins of replication?A complex of initiator proteinsIn late mitosis of the previous cell cycle into early G1 of the new cell cycle, what assembles at these origins of replication?
  118. 118Assembly of pre-replicative complexes (pre-RC) are essential for what?Directing replication as DNA synthesis only occurs at origins containing pre-RC complexes
  119. 119Pre-RC assembly on DNA is stimulated by what and inhibited by what?Stimulated by the APC/C; Inhibited by Cdk activity
  120. 120Pre-RC assembly on DNA is stimulated by the APC/C and inhibited by Cdk activity, ensuring assembly occurs when?Only in late mitosis and early G1
  121. 121Pre-RC assembly on DNA is stimulated by the APC/C and inhibited by Cdk activity, ensuring assembly occurs only in late mitosis and early G1 when APC levels are what and Cdk activity is absent or present?APC levels are high and Cdk activity is absent
  122. 122At the onset of S phase, a larger protein complex forms at pre-RC sites to form what?A preinitiation complex
  123. 123The pre-initiation complex unwinds the double stranded DNA to promote the loading of what?DNA polymerase and other replication enzymes
  124. 124The formation of what leads to the disassembly of the pre-replicative complex which does not reform at the origins of replication again until after chromosome segregation?2 replication forks
  125. 125The origin of replication is marked at all stages of the cell cycle by a complex of proteins called what?The origin of recognition complex (ORC)The origin of replication is marked at all stages of the cell cycle by a complex of proteins called what?
  126. 126In late mitosis and into early G1, what two proteins bind to protein components assembled on the origin?Cdc6 and Cdt1In late mitosis and into early G1, what two proteins bind to protein components assembled on the origin?
  127. 127In addition to the ORC, Cdc6 and Cdt1, 6 additional proteins called what, are assembled at the origin?Mcm related proteinsIn addition to the ORC, Cdc6 and Cdt1, 6 additional proteins called what, are assembled at the origin?
  128. 128What contains Cdc6, Cdt1 and Mcm1 proteins?The prereplicative complex (pre-RC)What contains Cdc6, Cdt1 and Mcm1 proteins?
  129. 129The 6 Mcm proteins act as a what?DNA helicase
  130. 130The central role of the prereplicative complex is to promote the loading of what? Which is required for what?DNA helicase which is required for DNA replication
  131. 131Upon activation of S-Cdk additional proteins associate with the origin to form what?The preinitiation complexUpon activation of S-Cdk additional proteins associate with the origin to form what?
  132. 132What promotes the disassembly of the pre-RC by phosphorylating Cdc6 (targeting Cdc6 for degradation) and the origin?S-CdkWhat promotes the disassembly of the pre-RC by phosphorylating Cdc6 (targeting Cdc6 for degradation) and the origin?
  133. 133S-Cdk promotes the disassembly of the pre-RC by phosphorylating Cdc6 (targeting Cdc6 for degradation) and the origin. What else is released from the origin?Cdt1S-Cdk promotes the disassembly of the pre-RC by phosphorylating Cdc6 (targeting Cdc6 for degradation) and the origin. What else is releas...
  134. 134To prevent Cdt1 from rebinding to the origin, Cdt1 associates with what inhibitory protein ?GemininTo prevent Cdt1 from rebinding to the origin, Cdt1 associates with what inhibitory protein ?
  135. 135Geminin accumulates in what two phases but is degraded by the APC in late M phase?Accumulates: S and M phases;
  136. 136The expression pattern for geminin allows for what?The re-establishment of Pre-RC complex assembly for the next cell cycle
  137. 137Targeted degradation of geminin and S-Cdk during late M phase allows both Cdt1 and Cdc6 protein to accumulate during what two phases? Promoting what?Late M phase and early G1 promoting prereplicative complex assembly
  138. 138What does SMC stand for?Structural Maintenance of Chromosomes
  139. 139Accurate chromosome segregation is dependent on what?Sister-chromatid cohesion
  140. 140What is essential for facilitating the attachment of the 2 chromatids to the opposite poles of the mitotic spindle?CohesionWhat is essential for facilitating the attachment of the 2 chromatids to the opposite poles of the mitotic spindle?
  141. 141Attachment of the 2 chromatids to the opposite poles of the mitotic spidle depends on a large protein complex called what?CohesionAttachment of the 2 chromatids to the opposite poles of the mitotic spidle depends on a large protein complex called what?
  142. 142Attachment of the 2 chromatids to the opposite poles of the mitotic spidle depends on a large protein complex called cohesion which is composed of what 4 protein subunits?Smc1, Smc3, Scc1, and Scc3Attachment of the 2 chromatids to the opposite poles of the mitotic spidle depends on a large protein complex called cohesion which is co...
  143. 143The cohesin complex assembles into what shaped structure? Where is it located?A ring-like structure along the length of each sister chromatidThe cohesin complex assembles into what shaped structure? Where is it located?
  144. 144What is the division of the cytoplasm?Cytokinesis
  145. 145When does cytokinesis begin and end?Cytokinesis follows every mitosis beginning in anaphase and ending in telophase
  146. 146Can mitosis occur without cytokinesis?Yes
  147. 147What kind of cells/organisms undergo mitosis without cytokinesis?1. Drosophila embryos
    2. Mammalian hepatocytes
    3. Heart muscle cells
  148. 148When cells undergo mitosis without cytokinesis, what kind of cell results?A multinucleated cell
  149. 149What is assembled from actin filaments, myosin II molecules and additional regulatory and structural proteins?Contractile RingWhat is assembled from actin filaments, myosin II molecules and additional regulatory and structural proteins?
  150. 150Which way does the contractile ring pull the membrane?Inward
  151. 151Where does the contractile ring form? During which phase of mitosis does it form?The contractile ring forms just beneath the plasma membrane during anaphase
  152. 152During contraction, what fuse with the plasma membrane to insert new membrane adjacent to the contractile ring to increase in the surface area of the plasma membrane?Intracellular vesiclesDuring contraction, what fuse with the plasma membrane to insert new membrane adjacent to the contractile ring to increase in the surface...
  153. 153The inward movement generated by actin and myosin contraction generates a what on the cell surface?Cleavage furrow
  154. 154What are the four events of cytokinesis?1. Initiation
    2. Contraction
    3. Membrane insertion
    4. Completion
  155. 155Contractile ring formation requires re-organization of what? Established in what kind of cells?Actin and myosin filaments established in interphase cells
  156. 156With entry into mitosis, what happens to the actin and myosin filaments established in the interphase cells?They disassemble and begin to form an contractile ring in anaphase
  157. 157Assembly of the contractile ring depends on what for the establishment of the parallel arrays of actin filaments?Formin
  158. 158What generates the force required for division?Actin filament arrays and assoicated myosin
  159. 159After cleavage, components of the cleavage furrow form what?The midbody
  160. 160The midbody contains overlapping what?Antiparallel interpolar microtubules
  161. 161After completion of division, the residual midbody may remain where?On the inside of the plasma membrane of each cell
  162. 162The residual midbody may have a role in helping to do what?Orient the spindle for the next cell division
  163. 163Assembly and function of the contractile ring is controlled by what?The monomeric GTPase, RhoA 
  164. 164RhoA is activated at the division site to promote what?1. Actin filament formation
    2. Myosin II assembly
    3. Ring contraction
  165. 165RhoA activity is controlled based on the nucleotide bound; Is it active or inactive when bound to GTP?Active
  166. 166RhoA activity is controlled based on the nucleotide bound; Is it active or inactive when bound to GDP?Inactive
  167. 167Nucleotide exchange is mediated by what?Rho GAP and Rho GEF proteins
  168. 168RhoA-GTP activates formins to stimulate what?Actin filament formation and Rho-activated kinases
  169. 169Rho-activated kinases phosphorylate the regulatory light chain of myosin II stimulating what?Myosin II filament formation and myosin motor activity
  170. 170Rho-activated kinases also inhibit what further stimulating myosin II phosphorylation and activation?Myosin phosphatase
  171. 171The activities of Rho-activated kinases, Actin and myosin II filament formation and myosin motor activity promote what?Contractile ring formation and contraction
  172. 172What are the steps in contractile ring formation?1. Activate RhoA with RhoGEF
    2. Active RhoA activates formins to stimulate actin filament formation and Rho-activated kinases; Active RhaA stimulates Rho-activated kinases
    3. Rho-activated kinases phosphorylate regulator light chain of myosin II
    4. Myosin II is activated
    5. Assembly and contraction of actin-myosin ring    What are the steps in contractile ring formation?
  173. 173Cytokinesis can only occur after what?Chromosome segregation
  174. 174The contractile ring must set up cellular division to partition to each daughter cell what?A complete set of chromosomes
  175. 175What is central to regulating both the timing and positioning of the contractile ring?The mitotic spindle
  176. 176During anaphase, the spindle generates a signal that initiates what? Where?Cleavage furrow formation at a position midway between the two spindle poles
  177. 177Since the signal comes from the anaphase spindle, this mechanism insures what?The correct timing
  178. 178What are the 3 general models proposed for the role of the mitotic spindle in specifying the site of cell division?1. The astral stimulation model
    2. The central spindle model
    3. The astral relaxation model
  179. 179What model has astral microtubules that carry "cleavage furrow" inducing signals to the cell cortex to promote furrow formation at a position half way between each pole?Astral stimulation model
  180. 180What model has astral microtubules that promote the relaxation of actin-myosin bundles all along the cortex except at the spindle equator which promotes cortical actin contraction at the cleavage furrow?Astral relaxation model
  181. 181What model has the spindle midzone which generates a "cleavage furrow inducing signal" that designates the position of the contractile ring?Central spindle stimulation model
  182. 182Identify the three general models proposed for the role of the mitotic spindle in specifying the site of cell division:A: Astral stimulation model
    B: Central spindle stimulation model
    C: Astral relaxation mode    Identify the three general models proposed for the role of the mitotic spindle in specifying the site of cell division:
  183. 183Cytokinesis in plants requires the formation of a what between the 2 daughter nuclei?A cell plate
  184. 184Cytokinesis in plants requires the formation of a cell plate between the 2 daughter nuclei by what kind of construction process?An "inside out" construction process
  185. 185When does cell plate assembly begin?Late anaphase
  186. 186Cell plate assembly is guided by what, a structure containing microtubule remains from the mitotic spindle?The phragmoplast
  187. 187In telophase, the remains of the mitotic spindle are used by motor proteins to deliver what? where?Golgi derived vesicles to the equator of the old spindle
  188. 188What substances do the vesicles contain that are necessary for the formation of the new cell wall?Polysaccharides and glycoproteins
  189. 189Which direction does the new wall form (inward or outward)?The new wall forms outward
  190. 190Vesicle fusion continues until it reaches what?The plasma membrane
  191. 191What is laid down and the plasma membrane surrounding the new cell wall fuses to complete the separation?Cellulose microfibers
  192. 192Give the steps of cell wall formation in a plant:1. The remains of the mitotic spindle are used by motor proteins to deliver Golgi derived vesicles to the equator of the old spindle
    2. Vesicle fusion begins
    3. Vesicle fusion continues until it reaches plasma membrane and forms the cell wall    Give the steps of cell wall formation in a plant:
  193. 193Cell division is typically what, with an equal partioning of material?Symmetrical
  194. 194Cell division symmetry results from the central localization of what?The mitotic spindle
  195. 195Give an example of organism that has assymetrical cell division:A fertilized egg from the nematode C. elegans.
  196. 196What is asymmetrical cell division?Cell division that produces 2 cells that differ in size and/or cytoplasmic content
  197. 197Asymmetrical cell division is established through the movement of the what?Mitotic spindle
  198. 198What re-positions the mitotic spindle?Astral microtubules and associated motor proteins
  199. 199Movement of the spindle generates what that ensures that only the posterior cell receives the partioned cytoplasmic components, or P-granules?A cleavage plane
  200. 200The same segregation process is repeated across several subsequent cell divisions to partition what?P-granules
  201. 201In the early Drosophila embryo the first 13 rounds of nuclear division occurs in a synchronous fashion without cytokinesis This generates what?A single large multi nucleated cell
  202. 202In the early Drosophila embryo, the first 13 rounds of nuclear division occurs in a synchronous fashion without what?Cytokinesis
  203. 203Nuclear division without cytoplasmic division speeds up what?The developmental process
  204. 204After 13 nuclear divisions, the nuclei migrate to the cell cortex and the plasma membrane extends inward around each nuclei to form individual cells in a process called what?'Cellularization'
  205. 205Organism size is determined by what three factors?1. Cell division (cell number)
    2. Cell death
    3. Cell growth
  206. 206Cell division, cell death and cell growth are controlled by what?Intracellular and extracellular events/molecules
  207. 207Extracellular molecules are soluble factors that are grouped into what three categories?1. Mitogens
    2. Growth factors
    3. Survival factors
  208. 208What are extracellular signals (stimulatory molecules) released from neighboring cells that stimulate cellular proliferation?Mitogens
  209. 209What was the first mitogen identified?Platelet-Derived Growth Factor (PDGF)
  210. 210What are anucleated cells that circulate in the blood and help stimulate blood clotting at sites of tissue injury?Platelets
  211. 211Platelets release factors that promote cell division for what?Wound healing
  212. 212PDGF is a protein that acts as a mitogen for a broad range of cells including what cells?1. Fibroblasts
    2. Smooth muscle cells
    3. Neuroglial cells
  213. 213PDGF stimulates what?Cell growth, survival, differentiation and migration
  214. 214What growth factor (EGF) which acts on epidermal and epithelial cells to stimulate cell division?Epidermal growth factor
  215. 215What mitogen is involved in stimulating division of red blood cell precursors?Erythropoietin
  216. 216What is the non dividing state in the cell cycle where cells exit from the cell cycle?G0
  217. 217Most of the cells in our body are in what state in the cell cycle where the cell cycle machinery is partially diassembled?G0
  218. 218The cell cycle machinery is dismantled and cell division rarely occurs in what state in the cell cycle?Terminally differentiated G0
  219. 219What stimulates cell growth by promoting protein synthesis?Growth factors
  220. 220What promotes cell survival by suppressing cell death?Survival factors
  221. 221Mitogens control the rate of cell division by acting in the G1 phase of the cell cycle to promote entry into what phase?S phase
  222. 222Mitogens bind to cell surface receptors triggering what?An intracellular kinase signalling cascade
  223. 223One major pathway, acting through the Ras GTPase, leads to the upregulation of what gene regulatory protein?MycOne major pathway, acting through the Ras GTPase, leads to the upregulation of what gene regulatory protein?
  224. 224Myc acts to increase the expression of G1 cyclins to increase what activity?G1-CDK activityMyc acts to increase the expression of G1 cyclins to increase what activity?
  225. 225Myc also upregulates the expression of genes responsible for what?Increasing cell growthMyc also upregulates the expression of genes responsible for what?
  226. 226The purpose of G1-CDK is to activate gene regulatory factors like what?E2FThe purpose of G1-CDK is to activate gene regulatory factors like what?
  227. 227E2F binds to the promoter region of genes that encode proteins necessary for S-phase entry including what?1. G1/S cyclins
    2. S cyclins
    3. Proteins involved in DNA synthesis and chromosome segregation    E2F binds to the promoter region of genes that encode proteins necessary for S-phase entry including what?
  228. 228In the absence of mitogen activation, E2F is complexed with what? Is it active or inactive?Retinoblastoma protein (Rb) and is inactiveIn the absence of mitogen activation, E2F is complexed with what? Is it active or inactive?
  229. 229With mitogen activation, G1-Cdk phosphorylates Rb decreasing its affinity for what?E2FWith mitogen activation, G1-Cdk phosphorylates Rb decreasing its affinity for what?
  230. 230Released E2F activates transcription of target genes to promote entry into what phase?S-phaseReleased E2F activates transcription of target genes to promote entry into what phase?
  231. 231One of the genes activated by E2F, is E2F itself, generating what kind of feedback loop? Does it increase or decrease E2F activity?A positive feedback loop increasing E2F activityOne of the genes activated by E2F, is E2F itself, generating what kind of feedback loop? Does it increase or decrease E2F activity?
  232. 232Intracellular and extracellular agents that induce DNA damage can do what to the cell cycle?Prevent entry into S phase and progression through the G2/M checkpoint
  233. 233DNA damage activates what pair of protein kinases?ATM/ATRDNA damage activates what pair of protein kinases?
  234. 234Knases (ATM/ATR) phosphorylate and activate what two kinases?Chk1 and Chk2Knases (ATM/ATR) phosphorylate and activate what two kinases?
  235. 235Chk1/Chk2 phosphorylate target proteins including what gene regulatory protein?p53Chk1/Chk2 phosphorylate target proteins including what gene regulatory protein?
  236. 236Phosphorylated p53 has reduced affinity for what ubiquitin ligase?Mdm2Phosphorylated p53 has reduced affinity for what ubiquitin ligase?
  237. 237Phosphorylated p53 has reduced affinity for the ubiquitin ligase Mdm2. This leads to an accumulation of what?Active and stable p53 proteinPhosphorylated p53 has reduced affinity for the ubiquitin ligase Mdm2. This leads to an accumulation of what?
  238. 238Active p53 activates the transcription of what CKI protein?p21Active p53 activates the transcription of what CKI protein?
  239. 239Chk1 and Chk2 kinases also phosphorylates what? Does it increase or decrease its activity?Cdc25 phosphatase inhibiting its activity
  240. 240DNA damage can result in what two results (with Mdm2)?1. Induce phosphorylation of the ubiquitin ligase, Mdm2
    2. Induce a decrease in Mdm2 protein production
  241. 241Either the phosphorylation of Mdm2 or the decrease in Mdm2 protein production leads to what?An increase in p53 protein amplifying p21 expression and G1/S-CDK and S/Cdk inactvation
  242. 242What binds to G1/S-Cdk and S-Cdk inhibiting their activities and blocking entry into the cell cycle?p21What binds to G1/S-Cdk and S-Cdk inhibiting their activities and blocking entry into the cell cycle?
  243. 243Accumulation of genetic damage in cells that lack a functional DNA response system leads to increased frequency of what?Cancer-promoting mutations
  244. 244Half of all human cancers are linked to mutations in what gene?p53
  245. 245A rare genetic disease in which patients are very sensitive to X-rays have mutations in the what gene?ATM
  246. 246Cells that accumulate severe DNA damage typically undergo what?Apoptosis
  247. 247Mutations in several of the components of the mitogen signaling pathway have been linked to what?Cancer
  248. 248Mutations identified as promoting cancer are called what?'Oncogenes'
  249. 249Mutations identified as promoting cancer are called 'oncogenes' and include what small GTPases?Ras and Myc
  250. 250Mutations that generate what form of the protein that stimulates excessive cell growth and proliferation in the absence of a mitogenic signal?'Hyperactive' form
  251. 251Upon detection of excessive mitogenic stimulation, levels of what is increased?A cell cycle inhibitor protein, ARF (alternate reading frame)Upon detection of excessive mitogenic stimulation, levels of what is increased?
  252. 252Arf binds to, and inhibits, the activity of what?Mdm2Arf binds to, and inhibits, the activity of what?
  253. 253Mdm2 ubiquitinates what promoting its degradation?p53Mdm2 ubiquitinates what promoting its degradation?
  254. 254When Mdm2 is sequestered by Arf, the levels of what increase?p53When Mdm2 is sequestered by Arf, the levels of what increase?
  255. 255The increase in p53 leads to what two outcomes?1. Cell cycle arrest
    2. Cellular apoptosis    The increase in p53 leads to what two outcomes?
  256. 256This safety mechanism is often inactivated in cancer cells by mutations in what?p53 and/or Arf
  257. 257For growth, increased cell proliferation must be accompanied by what?Cell growth
  258. 258Increased cell mass is dependent on extracellular signaling molecules called what?Growth factors
  259. 259Growth factors bind to cell surface receptors triggering the activation of what?An intracellular signalling cascade
  260. 260The intracellular signalling cascade increases the rate of protein synthesis while decreasing what?Protein degradation
  261. 261What are elevated during cellular growth?Nutrient uptake and ATP synthesis
  262. 262A major pathway activated by growth factors involves what kinase?PI3 kinaseA major pathway activated by growth factors involves what kinase?
  263. 263PI3 kinase converts PIP2 to what?PIP3PI3 kinase converts PIP2 to what?
  264. 264PI3 kinase converts PIP2 to PIP3 which activates what?The Tor kinasePI3 kinase converts PIP2 to PIP3 which activates what?
  265. 265Tor kinase activates targets which stimulate what?Protein synthesis and cell growthTor kinase activates targets which stimulate what?
  266. 266To maintain a constant cell size, what must be coordinated?Cell growth and cell division
  267. 267Growth and division are not coupled events for all cell types; but is coupled in what kind of cells?Proliferating cells
  268. 268Which pathway's rate of cell division is controlled by cell growth with division occuring only after a cell has reached a minimum size?Pathway AWhich pathway's rate of cell division is controlled by cell growth with division occuring only after a cell has reached a minimum size?
  269. 269Which pathway has factors can control both growth and division simultaneously?Pathway CWhich pathway has factors can control both growth and division simultaneously?
  270. 270Which pathway's cells growth and division are under the control of separate factors but it is the relative amount of each controlling factor that dictates division relative to growth?Pathway BWhich pathway's cells growth and division are under the control of separate factors but it is the relative amount of each controlling fac...
  271. 271For all organisms, it is the final total cell mass, not what, that controls cellular divisionActual cell number
  272. 272Salamanders of varying ploidy have a cell size that correlates with what?Genome content
  273. 273Salamanders are the same size but what differs?Their total number of cells differSalamanders are the same size but what differs?
  274. 274Although the haploid organism has 5X the number of cells as the pentaploid organism, what does not differ between the organisms?The total cell massAlthough the haploid organism has 5X the number of cells as the pentaploid organism, what does not differ between the organisms?
  275. 275There is a mechanism in place that measures what and not cell number when determining cell growth and division cycles?Cell mass

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Advanced Cell Biology Flashcards on The Cell Cycle, created by Tamara Johnson on 10/03/2015.
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Tamara Johnson
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