Meiosis is Cell Division that occurs only in sex cells or gametes and is necessary for reproduction. This Cell Division can only happen in Eukaryotic cells, such as plant and animals.
Mitosis is Cell Division in which a cell duplicates into two genetically identical daughter cells. In mitosis, chromosomes in the cell nucleus are separated into two identical sets of chromosomes, each in its own nucleus. This only occurs in Eukaryotic cells as well.
Mitosis
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Interphase: Mitosis covers all cell division except for making an egg or sperm. Mitosis begins with Interphase. Here the chromosomes replicate and the cell makes other materials necessary for cell divison. The cell increases in size.
As shown at the end of the pointer, the blackish circle inside the onion cell is the chromosomes all bunched together where they replicate.
As shown at the end of the pointer, the blackish circle inside the onion cell is the chromosomes all bunched together where they replicate.
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Prophase: In Prophase, the chromosomes become shorter, wider and easier to see with a microscope. The nuclear membrane disappears and the mitotic spindle forms. As in meiosis, microtubules extend from opposite poles of the cell and bind to chromosomes. Each chromosome is composed of two chromatids.
Late Prophase: The spindle fibers attach to the chromosomes.
Late Prophase: The spindle fibers attach to the chromosomes.
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Metaphase: In Metaphase, the chromosomes line up in single file, as specific proteins associated with the microtubules pull on them from each pole.
As shown at the end of the pointer, the microtubules begin to pull the chromosomes (The little lines).
As shown at the end of the pointer, the microtubules begin to pull the chromosomes (The little lines).
![Picture](/uploads/2/8/2/4/28248195/1398100689.jpg)
Anaphase: In Anaphase, the chromatids of each chromosome separate. One full set of chromosomes, composed of single chromatids, moves to one pole and one set moves to the opposite pole. As a consequence, each half cell has a full complement of genetic instructions.
As shown in the pointer, the chromosomes are being pulled away from each other (The little lines in the cell).
As shown in the pointer, the chromosomes are being pulled away from each other (The little lines in the cell).
![Picture](/uploads/2/8/2/4/28248195/1398100750.jpg)
Telophase and Cytokinesis: During Telophase and Cytokinesis, a nucleus reforms in each half of the cell, enclosing the chromosomes. The chromosomes resume their relaxed form, and the cell pinches and divides in two. In humans, the newly formed cells again possess two sets of 23 chromosomes.
As shown at the end of the pointer, two different nucleuses are formed (The little black dots).
As shown at the end of the pointer, two different nucleuses are formed (The little black dots).
Meiosis
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During Meiosis, the first round of phases is the exactly the same. The only difference is the end result. Instead of the cells dividing into two, and staying that way, in meiosis the two new cells each get a complete of organelles and chromosomes. Then comes Meiosis II: The second round of cell division.
Prophase II: In meiosis, this is the stage in which the chromosomes in their compact form attach to the newly formed spindle. (Remember that the cells as the end result of Meiosis 1 are going through their own phases of cell division)
Metaphase II: In this stage, the chromosomes are capture by one or more microtubules from each side. They line up in single file in the middle of the cell.
Anaphase II: The two chromatids of each chromosome detach from each other and move to opposite ends of the cell.
Telophase II and Cytokinesis: The nuclear membrane reforms, enclosing the chromosomes, and the cells pinch in two.
Since meiosis II began with two cells, the final product is four haploid cells (sperm).
Prophase II: In meiosis, this is the stage in which the chromosomes in their compact form attach to the newly formed spindle. (Remember that the cells as the end result of Meiosis 1 are going through their own phases of cell division)
Metaphase II: In this stage, the chromosomes are capture by one or more microtubules from each side. They line up in single file in the middle of the cell.
Anaphase II: The two chromatids of each chromosome detach from each other and move to opposite ends of the cell.
Telophase II and Cytokinesis: The nuclear membrane reforms, enclosing the chromosomes, and the cells pinch in two.
Since meiosis II began with two cells, the final product is four haploid cells (sperm).