Meiosis is a process in which a single cell divides twice to produce four cells containing half the original amount of genetic information. These cells are our sex cells – sperm in males, eggs in females. During the process of meiosis, a cell divides twice to form four daughter cells. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay. These four daughter cells have only half the number of chromosomes of the parent cell, called haploids. Meiosis produces our sex cells or gametes (eggs in females and sperm in males). Meiosis can be divided into nine stages. These are divided between the first time the cell divides (meiosis I) and the second time it divides (meiosis II): Meiosis IInterphase: First, the cell's DNA is copied, giving rise to two identical complete sets of chromosomes. SO. Outside the nucleus are two centrosomes each containing a pair of centrioles, these structures are essential to the process of cell division. During the process of interphase, microtubules extend from these centrosomes.Prophase I: The copied chromosomes have shortened into X-shaped structures that can be easily seen under a microscope. Then, every second chromosome is made up of two sister chromatids with identical genetic information. The chromosomes pair in such a way that the two copies of chromosome one are together, the two copies of chromosome two are also together. Pairs of chromosomes can then exchange small parts of DNA in a process called recombination or crossover. At the end of the first prophase, the membrane around the cell's nucleus dissolves, releasing the chromosomes. The meiotic spindle, made up of microtubules and other proteins, extends throughout the cell between centrioles. Metaphase I: Pairs of chromosomes line up next to each other along the center (the equator) of the cell. The centrioles are now at opposite poles of the cell and meiotic spindles extend from them. Then, the meiotic spindle fibers attach to one chromosome from each pair. Anaphase I: Next, the chromosome pair is separated by the meiotic spindle, which pulls one chromosome toward one pole of the cell and the other chromosome toward the opposite pole. During first meiosis, sister chromatids stay together, which is different from what happens during mitosis and meiosis II. Telophase I and cytokinesis: the chromosomes have completed their movement towards opposite poles of the cell. At each pole of the cell, a complete set of chromosomes comes together. A membrane forms around each set of chromosomes to create two new nuclei. Then, a single cell pinches off in the middle to form two separate daughter cells in which each contains a complete set of chromosomes in a nucleus. This process is known as cytokinesis. Meiosis IIProphase II: At this stage, there are two daughter cells with 23 chromosomes each (23 pairs of chromatids). In every two daughter cells, the chromosomes condense again into visible X-shaped structures, easily seen under a microscope. The membrane around the nucleus of each daughter cell dissolves, releasing the chromosomes. Then the centrioles duplicate and the meiotic spindle forms again. Metaphase II: In each of the two daughter cells, the chromosomes (a pair of sister chromatids) line up end to end along the cell's equator. Now the centrioles are at opposite poles in each cellgirls. The meiotic spindle fibers at each pole of the cell attach to each of the sister chromatids. Anaphase II: Sister chromatids are then pulled towards opposite poles due to the action of the meiotic spindle. The separated chromatids are then individual chromosomes. Telophase II and cytokinesis: Finally, the chromosomes complete their movement towards opposite poles of the cell. At each pole of the cell, a complete set of chromosomes comes together. A membrane forms around each set of chromosomes to form two new cell nuclei. This is the last phase of meiosis, however, cell division is still not complete without another round of cytokinesis. Once cytokinesis is complete, there are four granddaughter cells, each with half a set of chromosomes (haploid): in men, these four cells are all sperm; in women, one of the cells is an egg while that the other three are polar bodies which are (small cells that do not develop into eggs).Mitosis: Mitosis is the process by which the nucleus of a eukaryotic cell separates into two, followed by division of the cell mother into two daughter cells. The word "mitosis" means "son" and refers to the threadlike appearance of chromosomes as the cell prepares to separate. These tubules, collectively called spindles, develop from structures called centrosomes, with a centrosome located at each of the opposite ends, or poles, of a cell. As mitosis progresses, microtubules join with chromosomes, which have already duplicated their DNA and gathered at the center of the cell. The spindle tubules then contract and move toward the poles of the cell. As they move, they carry a copy of each chromosome with them towards opposite poles of the cell. This process ensures that each daughter cell will contain an exact copy of the parent cell's DNA. Mitosis is composed of five morphologically distinct phases: prophase, prometaphase, metaphase, anaphase and telophase. Each of these phases involves characteristic steps in the process of chromosome alignment and separation. Once mitosis is complete, the entire cell divides into two by the process called cytokinesisProphase which is the first stage of mitosis, occurring after the conclusion of the G2 part of interphase. During prophase, the chromosomes of parent cells, which were duplicated during S phase, condense and become thousands of times more compact than they were during interphase. Because each duplicated chromosome consists of two identical sister chromatids connected at a point called a centromere, these structures now appear as X-shaped bodies when viewed under a microscope. Several DNA-binding proteins catalyze the condensation process, including cohesin and condensin. Cohesin forms rings that hold sister chromatids together, while condensin forms a ring that rolls chromosomes into very compact shapes. Additionally, the mitotic spindle begins to develop during prophase. As the cell's two centrosomes move against opposite poles, the microtubules gradually assemble together, forming the network that will later separate the duplicated chromosomes. Once prophase is complete, the cell enters prometaphase, which is the second stage of mitosis. During prometaphase, phosphorylation of nuclear lamins by M-CDK causes the nuclear membrane to break down into numerous small vesicles. Thus, the spindle microtubules now have direct access to the cell's genetic material. Each microtubule is very dynamic, growing outward from the.