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Describing Cell Division

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Hypothesis: To observe cells located in an onion root tip and identify which stage of cell division the cells are in.

Introduction: Prevost and Dumas (1824)first proposed cell division, when they described cellular division in fertilized frog eggs. In 1858 Rudolf Virchow popularised the one-omnis cellulae cellula epigram ("Every cell originates from another existing cell like it"). Strasburger in 1873 found this epigram to be true, as he and Flemming found out that new nuclei was developed from pre existing ones. The term of mistosis was used to describe this process by Flemming in 1882(Tan 2006). Cell division is necessary for an organism to grow, mature and sustain tissue. The division of a individual cell produces a pair of daughter cells, each a fractional size of the primary cell. Prior to dividing each of the daughter cells will mature to the size of the original cell. When development is complete cell division continues as it is essential to survival. In order for cell division to be productive the genetic material and the nucleus must be twinned accurately and one copy must be distributed to each daughter cell. The copying of the cells genetic information is called DNA replication, nuclear division is called mitosis. Throughout the mitotic(M) phase the cell must undergo mitosis, a process that separates the duplicated chromosomes of a cell into two identical nuclei. It then divides to form two new respective cells during cytokinesis. Mitosis occurs solely in eukaryotic cells and the process differs in various groups (Raikov, 1994). Mitosis is split into distinct stages. Cells spend a minor part of their time involved in cell division. Somatic cells spend the bulk of their functional lives in a state known as Interphase. ...

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Prophase Chromosomes coil so tightly that they become visible as individual structures.
Metaphase Chromatids move to a narrow central zone called the metaphase plate. Metaphase ends when all the chromatids are aligned in the plane of the metaphase plate.
Anaphase The centromere of each chromatid pairs splits and the chromatids separate. The daughter chromosomes are pulled toward opposite ends of the cell along the chromosomal microtubules. Anaphase ends when the daughter chromosomes arrive near the centrioles at opposite ends of the cell.
Telophase During telophase, each cell prepares to return to the interphase state. The nuclear membranes form, the nuclei enlarge, and the chromosomes have relaxed and the fine filaments of chromatin become visible, nucleoli reapper and the nuclei resemble those of interphase cells. This stage marks the end of mitosis
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