Dr. Susan Kennedy
Introduction to Biology
January 28, 2012
Cellular reproduction is the process by which cells duplicate their contents and then divide to yield two cells with similar, if not duplicate contents. Life as we know it depends on the ability of cells to store, retrieve and translate the genetic instructions required to make and maintain a living organism. In this assignment, I will discuss two different types of cell reproduction, mitosis and meiosis and, include the different stages required in order for the reproduction to take place.
Mitosis is a process by which a cell divides to form two daughter cells and produces an almost carbon copy of the parent cell. The daughter cells will consist of the same number and type of chromosomes as the parent cell and will be identical to each other. Although cell division is the defining characteristic of mitosis, a number of events must take place during mitosis prior to the splitting of the cell. There are four phases that constitute the period in which cells make preparation for cell division. The four phases are prophase, metaphase, anaphase and telophase. Prophase, the first stage of mitosis during which the chromosomes become shorter, thicker and consist of two chromatids. At this time, the chromosomes are still enclosed in the cell nucleus within the nuclear envelope. The chromosomes also contain a centromere, which is necessary in later phases for attachment to microtubules for migration. Late in prophase, kinetochores assemble on the centromeres. Specialized microtubules, called kinetochore microtubules which will later, attach to these sites. Duplicated centrosomes, which are the organizing centers of microtubules, begin to separate towards opposite poles of the cell. The network of cytoskeletal components begins to break down and the mitotic spindle forms. The disruption of the nuclear envelope...
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