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Mitosis. Biology I G/T. Why do cells divide?. To make a new organism Growth Repair Replacement of normal cell loss Development. Structure of the Mitotic Chromosome Showing Sister Chromatids, Centromeres, and Spindle Fiber Attachment. Chromatid – ½ of a chromosome
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Mitosis Biology I G/T
Why do cells divide? • To make a new organism • Growth • Repair • Replacement of normal cell loss • Development
Structure of the Mitotic Chromosome Showing Sister Chromatids, Centromeres, and Spindle Fiber Attachment Chromatid – ½ of a chromosome Sister chromatid – each half of the same chromosome Centromere – complex of proteins attached to DNA holding the sister chromatids together
Stages of Mitosis S Stage Interphase
Interphase Animal Cell Interphase is not part of mitosis – it is the time between cell divisions Interphase includes G1, S, and G2 During interphase the cell is doing its normal metabolic activities like protein synthesis The cells are performing their duty as part of a tissue The DNA duplicates to get ready for mitosis The DNA is in chromatin form Plant Cell
Prophase Animal Cell The chromatin begins to condense into chromosomes and become visible in the nucleus The nuclear membrane begins to break down Centrosomes duplicate, form spindles, & move to the poles Spindle fibers attach to the chromosomes begin moving Plant Cell
Metaphase Plant Cell Animal Cell The chromosomes are lined up down the equator by the spindles
Anaphase Animal Cell The sister chromatids separate at the centromeres Each chromatid (now called a chromosome) heads to the pole of the cell Plant Cell
Telophase http://www.bioweb.uncc.edu/biol1110/Stages.htm
Telophase Animal Cell The chromosomes are completely to the opposite poles New membranes start to form around the DNA The chromosomes begin to decondense back to chromatin Cytoplasm begins to pinch in animal cells and a cell wall begins to form in plant cells – This is cytokinesis Plant Cell
After telophase is complete, the cells reenter interphase and go about their normal business The DNA is totally decondensed, new nuclei reformed, and there are totally 2 new cells Interphase
Differences Plant vs. Animal Cell Mitosis Cytokinesis in a plant cell Plant cells do not have centrioles in their centrosomes but animal cells do ????? Plant cells cannot pinch in due to the cell wall – a new cell wall forms down the middle from the endoplasmic reticulum Plant cells divide slower due to having to reform the cell wall Cytokinesis in an animal cell
Mitosis Quiz – Animal Cells Interphase Metaphase Anaphase Interphase Prophase Telophase
Mitosis Quiz – Plant Cells Metaphase Telophase Anaphase Interphase Prophase Interphase http://biology.nebrwesleyan.edu/benham/mitosis/