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28 Cards in this Set
- Front
- Back
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Components of G1-CDK
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Cyclin D
CDK 4 or 6 |
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Components of G1/S- CDK
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Cyclin E
CDK 2 |
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Components of S-CDK
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Cyclin A
CDK 2 |
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Components of M-CDK
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Cyclin B
CDK 1 |
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What 2 components result in a fully activated CDK
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1. Cyclin Binding
2. Phosphorylation or Dephosphorylation |
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How are cyclins degraded?
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Ubquitin-Proteasome System
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When when the cell cycle are no cyclin-CDKs active?
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Early G1-phase
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What is required to initiate the cell cycle?
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An external Mitogen
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Name 6 growth factors (mitogens)
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1. Fibroblasts
2. Epidermal 3. Vascular Endothelial 4. Platlet Derived 5. Nerve 6.Insulin-like |
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What does Rb inhibit?
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E2F
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What do G1-CDK and G1/S CDK directly act on to stimulate the cell cycle?
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Rb
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How is S-CDK stimulated?
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By the activity of G1-CDK and G1/S CDK--> increased expression of E2F
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Describe the full pathway resulting in Entry into S phase and activation of S-CDK
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1. An external mitogen binds to an RTK receptor activating the Ras G-protein and progressing through the MAPKKK pathway.
2. The MAPKKK pathway leads to activation of a gene regulatory protein 3. This gene regulatory protein results in the transcription of the myc gene and promotes the myc protein 4. The myc gene acts as a gene regulatory protein for 3 different processes A. Increased cyclin D expression with CDK 4 or 6 leading to G1-CDK B. Increased SCF production leading to increased degradation of P27. Degradation of P27 allows activation of G1/S-CDK C. Increased E2F synthesis leading to increased E2F activity. 5. G1-CDK and G1/S CDK lead to phosphoylation of Rb 6. Rb leads to increased E2F activity allowing entry into S phase |
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What does the SCF protein do?
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Degrades P27
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What does P27 do?
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Inhibits activation of G1/S-CDK
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If there is DNA damage, does the cell naturally progress into the S-Phase
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No!
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What is p53
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A transcription factor
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Which protein ubiquinates p53?
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Mdm2
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When is P53 phosphorylated?
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When there is DNA damage
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What is P21?
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A CDK inhibitor protein that inhibits G1-CDK and G1/S-CDK
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What is CDK-Activating Kinase (CAK)?
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Adds activating Kinase to M-CDK
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What is Wee 1?
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Adds inhibitory Kinase to M-CDK
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What is CDC25?
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A phosphatase that removes inhibitory phosphate from M-CDK thus activating it
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What activates CDC25?
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S-CDK
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What does M-CDK go on to activate?
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APC
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What is CDC20?
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Activates APC
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What is the APC?
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Anaphase Promoting Complex, ubquinates securin.
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What cleaves the cohesion complex holding chromatids todgether?
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Separase
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