Interphase:
Interphase is the period of the cell cycle in which the nucleus does not undergo division. It mainly occurs between mitotic or meiotic divisions. Its the resting stage between all cell divisions. It usually lasts between twelve to twenty-four hours in mammalian tissue. The cell is always synthesizing RNA during this period. Interphase can be divided into four steps which are Gap 0, Gap 1, synthesis phase, and Gap 2. In Gap 0 there are times when the cell may quit dividing. An example would be a cell that has reached an end stage of development and will no longer be able to divide. In Gap 1 the cells increase in size, producing synthesize and RNA protein. A cell cycle control mechanism is activated during this period and it makes sure that everything is ready for DNA synthesis. During the synthesis phase DNA replication occurs. This happens in order to produce two similar daughter cells. During Gap 2 between DNA synthesis and mitosis, the cell will continue to grow and produce proteins. At the end of the cycle it determines if the cell can proceed to enter mitosis and divide.
Prophase:
Prophase is the first stage of mitosis in which the chromosomes join together and become visible. The nuclear membrane breaks down and the spindle apparatus forms at opposite poles of the cell. Two centrosomes, in which replicate independently of mitosis have microtubule-activity increased due to the recruitment of the y-tubulin. The interesting feature of prophase is the setup of the mitotic spindle, in which is used to maneuver the chromosomes about the cell. The spindle is formed by extra parts from the cytoskeleton. The cell's centioles are duplicated to form two two pairs of centrioles. In which, each pair becomes the part of the mitotic center which forms the focus for an array of microtubules. This procees is called the aster. Two asters lie next to each other close to the nuclear envelope. Towards the end of prophase the asters pull apart and the spindle is formed.
Metaphase:
Metaphase is the stage that follows prophase and preceeds anaphase, in which the chromosomes are aligned along the metaphase plate. The genetic material is condensed into chromosomes. The chromosomes therefore become visible. The nuclear disappears and the chromosomes appear in the cytoplasm of the cell. As metaphase continues the cells break into two daughter cells.
Anaphase:
During anaphase two events occur. Anaphase begins when the duplicated centromeres of each pair of sister chromatids separate, and the now-daughter chromosomes begin moving toward opposite poles of the cell, due to the action of the spindle. The kinetochores begin to move towards the poles. Then the polar fibers elongate, which spreads the poles farther away from each other . Anaphase follows as the separated chromatids move toward opposite spindle poles. Wherever the centromere is located along the chromosome, a characteristic shape appears during chromosome movement. Then, at the end of anaphase a complete set of chromosomes is collected at each pole of the cell.
Telophase:
In the last stage of mitosis, which is telophase there are two separate groups of chromosomes at each pole. A nuclear envelope begins to form around each set of chromosomes to form two nuclei. It is temporarily in one cell. When the envelope reassembles RNA synthesis that begins to break down the chromosomes. This causes the nucleolus to reappear. The chromosomes of daughter cells are basically grouped in new nuclei. There are many changes that occur in telophase. Some of the changes is that the polar fibers continue to lengthen, nuclei begins to form at opposite poles, and the nuclear envelopes of these nuclei are formed from pieces of the parent cell's nuclear envelope, and from pieces of the endomembrane system. Also, nucleoli also starts to reappear. After these changes, the genetic contents of one cell has been divided equally into two.
By learning about the different types of stages in mitosis I now have a good understanding about how each stage works. I understand how to classify which cell is in what stage during mitosis.
During anaphase two events occur. Anaphase begins when the duplicated centromeres of each pair of sister chromatids separate, and the now-daughter chromosomes begin moving toward opposite poles of the cell, due to the action of the spindle. The kinetochores begin to move towards the poles. Then the polar fibers elongate, which spreads the poles farther away from each other . Anaphase follows as the separated chromatids move toward opposite spindle poles. Wherever the centromere is located along the chromosome, a characteristic shape appears during chromosome movement. Then, at the end of anaphase a complete set of chromosomes is collected at each pole of the cell.
Telophase:
In the last stage of mitosis, which is telophase there are two separate groups of chromosomes at each pole. A nuclear envelope begins to form around each set of chromosomes to form two nuclei. It is temporarily in one cell. When the envelope reassembles RNA synthesis that begins to break down the chromosomes. This causes the nucleolus to reappear. The chromosomes of daughter cells are basically grouped in new nuclei. There are many changes that occur in telophase. Some of the changes is that the polar fibers continue to lengthen, nuclei begins to form at opposite poles, and the nuclear envelopes of these nuclei are formed from pieces of the parent cell's nuclear envelope, and from pieces of the endomembrane system. Also, nucleoli also starts to reappear. After these changes, the genetic contents of one cell has been divided equally into two.
By learning about the different types of stages in mitosis I now have a good understanding about how each stage works. I understand how to classify which cell is in what stage during mitosis.
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