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SC- B-2.6: Summarize the characteristics of the cell cycle: interphase;the phases of mitosis, and plant & animal cytokinesis.

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Presentation on theme: "SC- B-2.6: Summarize the characteristics of the cell cycle: interphase;the phases of mitosis, and plant & animal cytokinesis."— Presentation transcript:

1 SC- B-2.6: Summarize the characteristics of the cell cycle: interphase;the phases of mitosis, and plant & animal cytokinesis

2  2 main reasons cells divide instead of growing larger 1. DNA overload  larger cells have greater demand on DNA 2. trouble moving nutrients & wastes in/out of cell  surface area/vol ratio: larger ratios more efficient

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4  in nuclei of eukaryotic cells  made up of: 1. DNA 2. Histones: proteins DNA wraps around

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7  series of events that cells go through as they grow & divide  only in eukaryotic cells  What a cell does in the cell cycle:  grow  prepares for division  divides into 2 daughter cells

8 The Cell Cycle

9  time between cell divisions  3 divisions: 1. Gap 1 (G1) 2. S Phase 3. Gap 2 (G2)

10  cells do most of their growing  make proteins & organelles  checkpoint  cells destined never to divide again leave cell cycle & enter G0

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12  synthesis phase  chromosomes duplicated  cells that enter S destined to go thru mitosis

13  usually shortest part of interphase  material needed for cell division produced  checkpoint

14  4 phases: 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase  each phase may last minutes to days depending on cell type  @ completion: 2 nuclei

15  longest phase of mitosis  chromosomes become visible (chromatin condenses)  centrioles separate & move to opposite sides of nucleus (animal cells )

16  centrioles start to organize mitotic spindle  nuclear envelope & nucleolus disappears

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18  chromosomes line up across center of cell = metaphase plate  centromere of each chromosome connected to spindle fiber

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20  centromeres split pulling sister chromatids apart  as soon as split they are called chromosomes  as long as they are moving they are in anaphase

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22  chromosomes disperse & are no longer visible  2 nuclear envelopes reform & each nuclei starts to form a nucleolus  spindle breaks apart  cleavage furrow becomes visible

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24  cytoplasm pinches in half  each daughter cell has identical set of duplicate chromosomes

25  rigid cell wall cannot “pinch” in half  Cell Plate starts to form during telophase  cell wall between 2 daughter cells

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