Sunday, August 12, 2012

Mitosis: The Phase of Mitosis

Mitosis is cell division that occurs indirectly Setjo (2004)said, Mitotic cell division is not occurs directly, there is a certain stages. These stages (phases) are present in mitotic include: prophase, metaphase, anaphase, and telophase

Mitosis occurs in somatic cells that are meristematic, which are cells that are growing (the root tip and stem end). The mitotic division process produces two identical daughter cells, and aims to maintain the same number of chromosome pairs.

For example, mitosis in plants occurs for 30 minutes to several hours and is part of a continuous process and constantly. On practical activities in secondary schools is usually used roots of onion (Allium cepa) because the root tissue of red onion (Allium cepa) is a tissue that is easy to be explored for the observation of mitosis (Sugiri, 1992).


The process of mitosis occurs along with the cleavage of the cytoplasm and materials outside the cell nucleus. At each diploid (2n) cell mitosis will produce two daughter cells, each of which remain diploid and have the same properties as the parent cell.

Mitotic sequence is as follows:

1. Prophase
Prophase is characterized by loss of nuclear membrane and nucleolus, followed by ‘spiralizing’ chromosome that looks thick.

2. Metaphase
The main characteristic of this phase is the movement of chromosomes to the center of the cell, often called the equatorial plane (metaphase plate), forming a cleavage spindle. Cleavage spindle is formed by microtubule activities.

3. Anafase
In this phase the chromosomes that accumulate in the cell apart and then gathered on each pole, so that there are two sets of chromosomes is seen on each pole.

4. Telofase
Telophase is the last phase, in telophase there are two stages, early telophase and late telophase. In the early telophase we can see any bulkhead that separates the cell into two. In the late telophase, we can see daughter cells are completely separated.


The picture below show the illustration of mitotic process [source: Chambel, 2008]:
[click picture to enlarge]


Source:
Anonim. 2004. The Cell Cycle & Mitosis Tutorial. (Online). http://www.biology. arizona.edu/cell_bio/tutorials/cell_cycle/cells3.html, diakses tanggal 28 Februari 2007

Campbell, N. A., Reece, J. B. & Mitchell. L. G. 2008. Biologi. Jilid 1. Edisi kedelapan. Jakarta: Erlangga.
Setjo, Susetyoadi. 2004. Anatomi Tumbuihan. Malang: JICA.


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