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Mitosis. Emile Mirzoevs Amanda Sabol Jocelyn Sickler. Stages of Mitosis. There are four stages of mitosis: Prophase Metaphase Anaphase Telophase. Photograph of a Animal Cell – Click Above. Photograph of a Plant Cell – Click Above. Prophase.
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Mitosis Emile Mirzoevs Amanda Sabol Jocelyn Sickler
Stages of Mitosis • There are four stages of mitosis: • Prophase • Metaphase • Anaphase • Telophase Photograph of a Animal Cell – Click Above Photograph of a Plant Cell – Click Above
Prophase • Chromatin fibers become more tightly coiled and condense into chromosomes that can be observed under a light microscope. • Each duplicated chromosome appears as 2 identical sister chromatids joined together. • The mitotic spindle begins to form. It is composed of centrosomes and the microtubules that extend from them. • The centrosomes begin to move away from each other, propelled by the microtubules. • Nuclear envelope fragments and the microtubules of the spindle invade the nuclear area and interact with the chromosomes. These extend toward the middle of the cell. • Each of the 2 chromatids of a chromosome now have a kinetochore; a specialized protein structure located at the centromere. • The microtubules attach to the kinetochore and jerk the chromosome back and forth.
Metaphase • Largest stage of mitosis; lasts 20 minutes • Centrosomes are now at opposite ends of a cell. • Centrosomes convene at the metaphase plate, an imaginary plane that is equidistant between the spindle’s 2 poles. The chromosome’s centromeres lie on the metaphase plate. • For each chromosome, the kinetochores of the sister chromatids are attached to kinetochore microtubules coming from opposite poles. • The entire apparatus of microtubules is called the spindle because of its shape.
Anaphase • Shortest stage of mitosis; only lasts a few minutes • Begins when the 2 sister chromatids of each pair suddenly part. Each chromatid thus becomes a full-fledged chromosome. • The two liberated chromosomes begin moving toward opposite ends of the cell, as their kinetochore microtubules shorten. • Cell elongates as the nonkinetochore microtubules lengthen.
Telophase • Two daughter nuclei begin to form in the cell. • Nuclear envelope arise from the fragments of the other parent cell’s nuclear envelope and other portions of the endomembrane system. • Chromosomes become less condensed. • Cytokinesis divides the cytoplasm into two.
Mitotic Phases in a plant cell • Photograph
Mitotic Phases of animal cell • Photograph
Bibliography • http://img.sparknotes.com/figures/D/d756b5b73abe2974f3521a828791899f/prophase.gif • http://img.sparknotes.com/figures/D/d756b5b73abe2974f3521a828791899f/metaphase.gif • http://withfriendship.com/images/h/35682/Anaphase-picture.gif • http://img.sparknotes.com/figures/D/d756b5b73abe2974f3521a828791899f/telophase.gif • http://faculty.cbu.ca/cglogowski/BIOL%20101%20IMAGES/PlantCellMitosis_CL.jpghttp://waynesword.palomar.edu/images/plmito3.jpg