Emile Mirzoevs Amanda Sabol Jocelyn Sickler There are four stages of mitosis: Prophase Metaphase Anaphase Telophase Photograph of a Plant Cell – Click Above Photograph of a Animal Cell – Click Above 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. 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. 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. 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. Photograph Photograph http://img.sparknotes.com/figures/D/d756b5b7 3abe2974f3521a828791899f/prophase.gif http://img.sparknotes.com/figures/D/d756b5b7 3abe2974f3521a828791899f/metaphase.gif http://withfriendship.com/images/h/35682/Ana phase-picture.gif http://img.sparknotes.com/figures/D/d756b5b7 3abe2974f3521a828791899f/telophase.gif http://faculty.cbu.ca/cglogowski/BIOL%20101%2 0IMAGES/PlantCellMitosis_CL.jpg http://waynesword.palomar.edu/images/plmito 3.jpg