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Chapters 10 and 11: Cell Growth and Division
Mitosis/Meiosis/Cancer
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Why is it necessary for cells to divide?
DNA Overload-not enough information for the cell as it grows larger in size To improve material exchange Volume of cell increases faster than surface area
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What is Cell Division ? process where a cell divides into two new daughter cells Before cell division takes place, the cell must copy or replicate its DNA. Each daughter cells gets a complete copy of the original DNA Cell division has 2 parts Mitosis: division of nucleus and DNA Cytokinesis: division of cytoplasm and organelles
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Chromosomes- condensed form of DNA
Sister chromatids- 1 chromosome and a copy of it “tied” together before the cell divides Centromere- the chemical “knot” holding sister chromatids together LABEL THE DIAGRAM IN YOUR NOTES.
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Figure 10–4 The Cell Cycle
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Figure 10–4 The Cell Cycle G1 phase M phase S phase G2 phase
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Figure 10–5 Mitosis and Cytokinesis
Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Prophase-Phase #1 of Mitosis
Longest Phase-50% to 60% of total time to complete mitosis Chromatin condenses into Chromosomes Centromeres connect sister chromatids Centrioles separate to opposite poles Spindle is organized Nucleolus disappears and nuclear envelope breaks down.
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Figure 10–5 Mitosis and Cytokinesis
Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Metaphase-Phase #2 of Mitosis
Centromeres attach to spindle fibers Chromosomes line up across the equator of the cell-metaphase plate
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Figure 10–5 Mitosis and Cytokinesis
Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Anaphase-Phase #3 of Mitosis
Sister chromatids separate becoming individual chromosomes and moving to opposite poles of cell
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Figure 10–5 Mitosis and Cytokinesis
Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Telophase-Phase #4 of Mitosis
Chromosomes disperse into chromatin Nuclear envelope re-forms around each cluster of chromatin Spindle breaks apart Nucleolus visible in each new daughter cell
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Figure 10–5 Mitosis and Cytokinesis
Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Cytokinesis Division of cytoplasm and organelles
Animal Cells: Cleavage Furrow-cell membrane pinches inward Plant Cells: Cell Plate-develops into separating membrane (cell wall appears shortly after)
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Figure 10–5 Mitosis and Cytokinesis
Spindle forming Centrioles Nuclear envelope Chromatin Centromere Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Cytokinesis
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Prophase Interphase
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Metaphase Prophase
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Anaphase
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Telophase
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Cancer Disorder in which some cells lose ability to control growth
Form tumors Carcinogen- cancer causing agent (ex. Cigarettes, UV radiation from sun)
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Regulating the Cell Cycle
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Asymmetrical, Borders, Color, Diameter, Elevation
Skin Cancer : Melanoma Asymmetrical, Borders, Color, Diameter, Elevation
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Meiosis Cell Division to produce gametes-sex cells (sperm and egg)
Number of chromosomes per cell is cut in half through separation of homologous chromosomes in diploid cell
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Homologous Chromosomes
Chromosomes containing same genes 1 chromosome from mom and 1 chromosome from dad Diploid=2N-cell that has both copies meaning 2 complete sets of genes/chromosomes (all regular cells-somatic cells) In humans 2n=46 Haploid=N-cell that has one set/copy (gametes/sex cells) In humans n=23
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Crossing over occurs during Prophase I, and homologous chromosomes exchange portions of their chromatids (DNA)
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Figure Meiosis Section 11-4 Meiosis I
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Figure Meiosis Section 11-4 Meiosis I Meiosis I
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Figure Meiosis Section 11-4 Meiosis I Meiosis I
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Figure Meiosis Section 11-4 Meiosis I
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Figure Meiosis Section 11-4 Meiosis I
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Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II
Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.
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Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II
Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.
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Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II
Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.
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Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II
Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.
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Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II
Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.
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Gamete Formation In males4 sperm cells are produced
In females1 egg cell is produced Other 3 cells=polar bodies-not involved in reproduction and eventually degenerate b/c do not receive enough cytoplasm containing nutrients
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Mitosis Meiosis Results in production of 2 genetically identical diploid cells Creates all cells in the body EXCEPT gametes PMAT Results in production of 4 genetically different haploid cells Creates gametes Reason why everyone is slightly different EXCEPT for identical twins/triplets PMAT x2 Tetrads form and crossing over happens
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