BB lecture 12-5 cell cycle, mitosis

BB lecture 12-5 cell cycle, mitosis - Chapter 12...

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Chapter 12 (pp.219-228) Nuclear division (mitosis) and the cell cycle Learning objectives Know the phases of the cell cycle Know the phases of mitosis and how/where chromosomes move Compare cytokinesis in animal and plant cells Describe the division of prokaryotes by binary fission Describe the roles of microtubules and microfilaments Contrast the mitosis of dinoflagellates and diatoms with that of animal cells Terms to know include: centrosome, centriole, centromere, chromatid, cleavage chromosomal mutation by deletion, inversion, duplication, translocation…
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The cell cycle of “typical” human cell: 1 division/24 hours INTERPHASE G 1 S (DNA synthesis) G 2 Cytokinesis Mitosis MITOTIC (M) PHASE [10-12 hours] [< 1 hour] [5-6 hours] [4-6 hours]
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Figure 12.4 Chromosome duplication and distribution during cell division 0.5 µm Chromosome duplication (including DNA synthesis) Centromere Separation of sister chromatids Sister chromatids Centromeres Sister chromatids Before duplication, each chromosome has a single DNA molecule. Once duplicated, a chromosome consists of two sister chromatids connected at the centromere. Each chromatid contains a copy of the DNA molecule. Mechanical processes separate the sister chromatids into two chromosomes and distribute them to two daughter cells.
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Telomere/centromere. .from the Greek words telos meaning “ end ”, or centros meaning central ”, and meros meaning “ par t” ...
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The Mitotic Spindle: In detail The mitotic spindle is made of microtubules that control movements of chromosomes Assembly of spindle microtubules begins in the centrosome , the microtubule organizing center ( MOC ) The centrosome replicates, forming two centrosomes that migrate to opposite ends of the cell, as spindle microtubules grow out from them An aster (a radial array of short microtubules) extends from each centrosome The spindle includes the centrosomes, the spindle microtubules, and the asters Some spindle microtubules attach to the kinetochores of chromosomes and move the chromosomes to the metaphase plate – these are called kinetochore microtubules In anaphase, sister chromatids separate and move along the kinetochore microtubules toward opposite ends of the cell The microtubules shorten by depolymerizing at their kinetochore ends Nonkinetochore microtubules from opposite poles overlap and push against each other, elongating the cell
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During anaphase, do kinetochore microtubules shorten at their spindle pole ends or their kinetochore ends? EXPERIMENT
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This note was uploaded on 03/19/2008 for the course BIO 311C taught by Professor Satasivian during the Fall '08 term at University of Texas at Austin.

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BB lecture 12-5 cell cycle, mitosis - Chapter 12...

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