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5.2 Mitosis and Cytokinesis KEY CONCEPT Cells divide during mitosis and cytokinesis.

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Presentation on theme: "5.2 Mitosis and Cytokinesis KEY CONCEPT Cells divide during mitosis and cytokinesis."— Presentation transcript:

1 5.2 Mitosis and Cytokinesis KEY CONCEPT Cells divide during mitosis and cytokinesis.

2 5.2 Mitosis and Cytokinesis One long continuous thread of DNA coiled around histones (proteins) is called chromatin. One half of a duplicated chromosome is a chromatid. Sister chromatids are held together at the centromere. Telomeres protect DNA and do not include genes. Condensed, duplicated chromosome chromatid centromere telomere

3 5.2 Mitosis and Cytokinesis Chromosomes condense at the start of mitosis. DNA wraps around proteins (histones) that condense it. DNA double helix DNA and histones Chromatin Supercoiled DNA

4 5.2 Mitosis and Cytokinesis Parent cell centrioles spindle fibers centrosome nucleus with DNA 1.Interphase prepares the cell to divide. DNA is duplicated. B. Mitotic Phase- Mitosis and cytokinesis produce two genetically identical daughter cells.

5 5.2 Mitosis and Cytokinesis Cell structures and mitosis Centrosomes-organelle that is the main microtubule organizing center. Aster-cellular star shaped structure that forms around the centrosome-made of microtubules Equator-mid section of the dividing cell Cleavage furrow - indentation that begins the formation of the new cell membrane Cell plate- the new cell wall Kinetorchore fibers- attachment points on the centromere where the chromosomes are held together to make an X Spindle- fibers that separate the chromosomes Microtubules-hollow, protein fibers and rods. Cytokinesis-division of the cytoplasm results two daughter cells.

6 5.2 Mitosis and Cytokinesis 2.During prophase, chromosomes condense, nuclear membrane, nucleus, and nucleolus disappear, spindle fibers form, centrioles make spindle fibers

7 5.2 Mitosis and Cytokinesis –3.During metaphase- spindle fibers randomly align sister chromatids in the middle of the cell (equator)

8 5.2 Mitosis and Cytokinesis –4.During anaphase- spindle fibers retract and pull the sister chromatids opposite sides of the cell (poles)

9 5.2 Mitosis and Cytokinesis –5.During telophase- chromosomes uncoil, nuclear membrane reforms, nucleolus reforms.

10 5.2 Mitosis and Cytokinesis 6.Cytokinesis-division of the cytoplasm –In animal cells, the membrane pinches closed at a point called cleavage furrow. –In plant cells- vacuoles join together and form a cell plate. Result-2 identical daughter cells with identical copies of genetic material- DNA

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