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Mitosis

Mitosis. Overview. Overview. Mitosis or cell division enables organisms to grow and reproduce. Occurs in four main steps (prophase, metaphase, anaphase, and telophase). During the process “replicated genetic material in a parent cell is equally distributed to two daughter cells”

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Mitosis

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  1. Mitosis Overview

  2. Overview • Mitosis or cell division enables organisms to grow andreproduce. • Occurs in four main steps (prophase, metaphase, anaphase, and telophase). • During the process “replicated genetic material in a parent cell is equally distributed to two daughter cells” • Accounts for about 10% of the time in the cell cycle

  3. Prophase • Nucleoli disappear • Chromatin fibers become coiled into chromosomes (two chromatids attached at a centromere). • Spindle fibers form in the cytoplasm at opposite ends of the cell. • Later, the nuclear envelop dissolves. • Centrioles on each side of the cell attach their spindle fibers to the kinetochores, located on each chromosome’s centromere, aligning the chromosomes in the middle of each cell. Images

  4. Prophase Pictures ASCARIS MEGALOCEPHALA Onion Cell Animal Plant Info

  5. Metaphase • Accounts for 4% of the cell cycle duration • Centrosomes are at opposite poles of the cell • The chromosomes are now at their most highly condensed form, and are arranged at the center of cell, along the metaphase plate, equidistant from the two poles. • Sister chromatids face opposite poles of the cell to prepare for division. Images

  6. Metaphase Pictures ASCARIS MEGALOCEPHALA Onion Cell Animal Plant Info

  7. Anaphase • Sister chromatids separate • Spindle fibers move the separated chromatids to opposite poles of the cell • The poles of the cell move further from each other, elongating the cell • Each pole has an equivalent and complete set of chromosomes. Images

  8. Anaphase Pictures ASCARIS MEGALOCEPHALA Onion Cell (Mid Anaphase) Animal Plant Info

  9. Telophase • Microtubules continue to elongate the cell • Daughter nuclei begin to form at the poles where the chromosomes have gathered • Nuclear envelopes form from fragments of the old nuclear envelope • Nucleoli begin to reappear • Cytokinesisis underway-in animals a cleavage furrow appears Images

  10. Telophase Pictures ASCARIS MEGALOCEPHALA Onion Cell Animal Plant Info

  11. Glossary Centrosome- an area in the cell where microtubles are produced (within an animal cell centrosome there is a pair of the centrioles). Cleavage furrow- The term to describe the pinching of an animal cell into two cells, the mechanism of cytokinesis. Cytokinesis- the division of the original cell's cytoplasm. Kinetochore- a specialized region of the centromere to which spindle fibers attach, pulling the chromosome to the center of the cell. Spindle Fibers- “An aggregate of microtubules that move chromosomes during cell division.”

  12. Works Cited http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20101/Bio%20101%20Lectures/Mitosis/mitosis.htm http://library.thinkquest.org/C0123260/basic%20knowledge/mitosis.htm http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20101/Bio%20101%20Laboratory/mitosis/ascaris.htm http://www.superstock.com/stock-photography/Ascaris+megalocephala http://biology.about.com/od/mitosis/ss/mitosisstep_2.htm http://biology.about.com/od/mitosis/ig/Mitosis-Image-Gallery/

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