1. The document discusses the process of mitosis and provides details on the structure of chromosomes, organelles involved in cell division, and the steps of mitosis. 2. Chromosomes are tightly packed bundles of DNA that contain identical strands called sister chromatids connected at the centromere. 3. Key organelles involved in mitosis include the nuclear membrane, cytoskeleton, and mitotic spindle which contains centrioles, asters, and kinetechore fibers that pull chromosomes apart.

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2. Agenda NOTES: Mitosis Details of Chromosome Structure Organelles Involved in Division Mnemonic Device for PMATC Details of each step of Mitosis

3. Structure of Chromosomes Chromosomes are tightly packed bundles of DNA that look like the letter X. The left and right halves of chromosomes are identical strands called “Sister Chromatids”. The spot where the chromatids connect together is called the centromere.

4. Chromosomes

7. Nuclear Membrane The Nuclear Membrane is the outer skin of the nucleus. It is the the “Sac” that holds Chromatin. It is sometimes called the Nuclear Envelope.

8. Cytoskeleton The cytoskeleton is a network of protein fibers that run throughout the cell. These fibers maintain the shape of a cell and act as tiny muscles to stretch and move.

9. BLUE = Microtubules GREEN = Intermediate Filaments RED = Microfilaments

10. Mitotic Spindle The mitotic spindle is a collection of fibers that pull chromosomes apart during mitosis. It has 3 major components Centrioles: A pair of organelles that anchor the mitotic spindle at opposite ends of the cell. Asters: Short fibers that radiate out from the centrioles in order to hold their position Kinetechore fibers: Long fibers that pull chromosomes apart and toward either end of cell.

12. Steps of Mitosis Mitosis is the division of Eukaryotic Cells. It has 5 steps Prophase Metaphase Anaphase Telophase Cytokinesis

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17. Prophase Chromatin in the DNA coils to make chromosomes The nuclear membrane breaks down, releasing chromosomes into the cytoplasm Centrioles move to opposite ends of the cell and the mitotic spindle forms between them. Kinetechore fibers from each half of the spindle attach to the centromere region of each chromosome.

20. Metaphase Kinetechore fibers of the spindle move chromosomes towards center of the cell. By the end of this phase all chromosomes are lined up along the “equator”.

21. Metaphase Chromosomes lined at the Equator Asters at the poles Spindle Fibers

23. Anaphase Chromosomes are split apart and Sister chromatids are pulled in opposite directions This occurs very quickly ( Less than 5 minutes )

24. Anaphase Sister Chromatids being separated

25. Telophase Sister chromatids arrive at opposite ends of the cell and begin converting back into chromatin. A nuclear envelope forms around each set of DNA to create new nuclei. The mitotic spindle is broken down.

27. Cytokinesis The Cell Membrane pinches together between the 2 newly formed nuclei This movement is done by the cytoskeleton.

28. BrainPOP: Mitosis

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