Mitosis And Meiosis
Mitosis and Meiosis describes the way in which cells divide and reproduce. Cell reproduction is fundamental in understanding how species such as humans reproduce.
One of the ways in which cells reproduce is called Mitosis and it is a type of cell division, which means that a parent cell divides into two daughter cells. The process of mitosis is divided into four stages known as: prophase, metaphase, anaphase and telophase. Mitosis is a form of asexual reproduction used by single-celled organisms for reproduction, as well as being used for the growth of tissues, fibers and membranes. Mitosis is a process used in all organisms.
During the prophase, the membrane dissolves. In the metaphase proteins in the chromosome move the chromosome, placing it at the center of the cell. During the anaphase chromosomes are split and moved towards the end of the cell, the two portions of the cell are referred to as daughter chromosomes. During the final phase, telophase, the two chromosomes attach to their parent cell, and the previous stages are repeated- but in reverse. After the four stages are completed, a process known as cytokinesis takes place, in which the daughter chromosome becomes a daughter cell. Once this is complete two new cells are formed which are identical to the original parent cell.
Meiosis is a specific cell division that results in either a sperm or an egg, which carries one half of the chromosome found in the parent cell. There is only one main purpose to Meiosis, which is for sexual reproduction and the propagation of the species. This process occurs in humans, animals, plants and fungi. Like meiosis this procedure is also a multistage procedure.
The two phases of meiosis is called meiosis 1 and meiosis 2 and both stages have four sub-stages of their own. Meiosis 1 has phases consisting of prophase 1, metaphase 1, anaphase 1 and telophase 1. Likewise meiosis 2 has prophase 2, metaphase 2, anaphase 2 and telophase 2. In meiosis 1, a germ cells splits into two diploid cells and there is an exchange of genetic material, however the processes of meiosis 2 is similar to the process witnessed in mitosis
Scientists research these processes to find relationships within a cell’s structure and such knowledge can be applied in biomechanics and nanotechnology. It is hoped that a further understand of these processes can lead to better medical procedures and technology.
July 21, 2005
In the lab exercise related to Mitosis, we view various slides containing cells undergoing Mitosis. We viewed 2 different specimens; a slide of an onion root tip and a slide of Ascaris eggs. Some of the cells are at different phases of Mitosis (Interphase, Prophase, Metaphase, Anaphase, Telophase). We viewed it under HPO and LPO. Chromosomes were visible in both the LPO and the HPO although the spindle fibers were not very visible because of limitations in the light microscope. The exercise was successful because we were able to see different cells at different phases of Mitosis. We were able to discover the differences between each reaction and why Mitosis is divided into different phases. We were also able to label some of the parts in the cells undergoing mitosis. Overall, we discovered a lot of new things about Mitosis.
LPO- Low power objective
HPO- High power objective
What if your cells don't reproduce or increase in number? What will eventually happen if your arm was wounded by a knife? If cells don't reproduce, how will your arm heal? All living organisms contain cells and in order for them to grow, survive, and eventually reproduce, the cells in their body should be able to multiply. The repair of the damaged parts of different organisms also requires the cells to increase in number in order to replace the damaged ones. The growth of the cells of many organisms generally has 3 main phases; cell division, cell enlargement, and cell differentiation. The types of cell division are usually Meiosis and Mitosis, in which the latter maintains the chromosome number of parent cells to daughter cells. Mitosis is generally divided into five stages; Interphase, Prophase, Metaphase, Anaphase, and the Telophase. The Interphase may also be referred to as the "resting stage" mainly because there seems to be no apparent changes occurring within the cell. The next stage is the Prophase wherein there is a gradual appearance of chromosomes and spindle fibers and also the disappearance of the nuclear membrane and the nucleoli. The Metaphase is the stage where there is a horizontal alignment of the chromosomes at the equitorial plate. The Anaphase is characterized by the division of the Centromere and the separation of the sister chromatids. The centromeres are pulled by spindle fibers toward the opposite poles of the cell. The Telophase is the stage wherein there is gradual disappearance of the chromosomes and spindle fibers, and the appearance of the nuclear membrane of each daughter cell. It is also during this stage where there is division of cytoplasm, usually a cell plate in plants and cleavage in animals.
All of the stages described above are intertwined with each other in a sense that Mitosis is a continuous process where the stages merge with another stage without any definite demarcation. All of these stages are important for an organism to be able to distribute...
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