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20 Cards in this Set
- Front
- Back
Phase in which cell doubles in size and DNA content
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Interphase
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Phases of Interphase
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G1
S G2 |
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G0
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Quiescent phase no more synthesis occurs
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G1
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-period of after mitosis
-RNA and Protein synthesis -Cyclin D & E bind to Cyclin Dependent Kinase (CDK) to initiate progression to S |
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S
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- DNA replication
- Protein synthesis - Chromosomal duplication - Centromere duplication - Cyclin A binds to CDK to enter G2 |
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G2
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-2-4 hours
-Centrioles grow -Energy for mitosis stored -RNA and Proteins for mitosis synthesized -Tubulin for spindle apparatus synthesized -Cyclin B initiates entry to M phase |
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Mitosis
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-2 identical daughter cells
-Prophase -Prometaphase -Metaphase -Anaphase -Telophase |
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Prophase
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-nuclear envelope and nucleolus begin to disappear
-chromosomes condense -2 sister chromatids attached at centromere -Centrioles migrate to opposite poles giving rise to astral rays and spindle fibers -DNA = 4n (doubled) |
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Centrosome
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-centrioles
-α-tubulin rings in a cloud -Microtubule Organizing Center (MTOC) |
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Chromosome
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-2 parallel sister chromatids attached at centromere
-Kinetochores form at centromeres, MTOC |
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Prometaphase
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-nuclear envelope disappears
-kinetochore microtubules form -polar microtubles (spindle mt not attached to kinetochore) |
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Metaphase
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-chromosomes align at equatorial plate of mitotic spindle and attach to spindle mt at kinetochore
-4n DNA |
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Anaphase
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-chromatids separate at centromere cohesion degrades, spindle elongates
-4n DNA -Contractile ring of actin microfilaments forms around cell |
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Anaphase A
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-kinetochores shorten, pulling daughters to poles
-(-) end directed motor protein at kinetochore |
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Anaphase B
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-overlapping polar mt slide against each other pushing on opposite pole and pulling towards its own pole
-(-) end directed motor proteins at astral mt. binding to cell cortex -(+) end directed motor proteins at midbody of overlapping polar mt. |
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Telophase
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-each daughter reaches a pole
-mt in the overlapping polar midbridge mt depolymerize cytokinesis -nuclear envelope reforms -nucleoli reappear -cell returns to interphase appearance -2n DNA |
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Microtubules
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-Mitotic spindle
-Polar: go toward the equatorial plane -Astral: go towards one end of pm -Kinetochore: from the centromere -Grow towards (+) end -No spindle no cell division, so cancer drug target -Taxol: stabilizes mt. so no division -Anti-MT: Colchichine; Vinblastine; Nocodazole |
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Actin
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-contactile ring during cytokinesis
-bipolar myosin II filaments slide actin against itself |
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Intermediate Filaments
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-breakdown of and reassembly of nuclear envelope
-phophorylation of lamins triggers disassembly of nuclear lamina -P added around prophase, and removed after prophase |
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Fate of Organelles in Mitosis
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-ER, Golgi vesiculate when nuclear envelope breaks down, reform in telophase
-Mitochondira, peroxisomes and lysosomes remain unchanged |