Cell Division: Meiosis
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Living organisms have the ability to reproduce. Meiosis is the process by which organismsâ sex cells replicate in order to reproduce an offspring. Meiosis begins with one cell and after two divisions, four daughter cells containing half the needed DNA is the result. This process causes a genetic shuffle as the DNA (or more specifically genes) that is chosen for each new cell is completely random. There are five phases in the meiosis process but most of them occur twice. These five phases are: prophase, metaphase, anaphase, telophase, and interphase. The first round of divisions is often referred to as Meiosis I. Basically the chromosome pairs line up in the middle of the cell and as the cell divides, they are pulled to either side. During this process, the chromosomes divide randomly so that no two cells contain the exact same match. At the end of Meiosis I, there are two new cells. If this division where occurring in a normal body cell, this would be the end of the replication process. Before the cells begin Meiosis II, they enter a brief stage called interphase. Meiosis II contains the same phases as Meiosis I. The daughter cells produced in Meiosis I each go through a division. This time the DNA does not divide. Some DNA goes with each new cell so the new cells have half as much DNA as the original cell. In order for these new cells to become a new organism, they must combine with other cells of the same kind. |
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