Mitosis

=__The Cell Cycle __=

The cell cycle is a regular sequence of growth and division of a cell and is divided into two phases; interphase and M phase. The first process is interphase which is divided into three phases, G1, S, and G2 phases. G1 is the longest phase in which the cells performs normal cell growth and normal cell functions where the DNA in the cell is loosely organized called chromatin, resulting in the longest phase of the cell cycle. The next phase is S phase in which the cell carries out DNA replication. DNA replication is when the cell makes a copy of the DNA for the daughter cell. During the last phase of interphase which is G2 phase, the cell prepares for cell division. With this the cell checks if it needs more of any organelles, proteins, etc. for the daughter cell. The cell is now able to enter M phase where cell division occurs, and this is divided into two sections, mitosis and cytokinesis.

__Mitosis __

Mitosis is the process of cell division which is divided into four phases; prophase, metaphase, anaphase and telophase. Cells divide for two reasons, because they need to repair old and dying cells and for cell growth. 

__Prophase__ is the first stage of mitosis and in this phase the loosely organized chromatin condenses into highly organized chromosomes. The nuclear envelope begins to disappear while the centrids start to separate to opposite sides of the cell and the spindle fibers begin to form. The next stage of mitosis is metaphase. In __metaphase__ the centrioles are now at opposite side of the cell and the highly organized chromosomes line up in the middle of the cell. Each one of these chromosomes are connected to a spindle fiber at its centromere. In __anaphase__, the third stage of mitosis the chromosomes turn into sister chromatids and are separated into individual chromosomes, which are pulled towards opposite sides of the cell. The final stage of mitosis is telophase. In __telophase__ the chromosomes gather at oppostie sides of the cell and two nuclear evenlopes begin to form, this marks the end of mitosis.

Mitosis Animantion []

Mitosis Visual Video media type="youtube" key="VGV3fv-uZYI?fs=1" height="385" width="640"

__Cytokensis __

The next stage of the cell cycle is cytokensis. Ctyokensis is when the cytolplasm and the cell membrane preform celvage furrow in animal cells and the cell pinches in half. But in plant cells a cell plate forms seperating the two new identical daughter cells. Now the cell will repeate this process several times over its lifetime until it eventually dies.

Clevage furrow and cell plate formation in Cytokensis. __Cancer __

Cell divison is very important and if this process is done incorectly there can be very serious side effects. For example one of the most know effects on the body cause by a mutation during cell divison is cancer. __Cancer__ is caused becuase a mutation occurs that causes cells to replicate even though the tissue doesn't need replacement at the time. These newly mutated cells keep on dividing and from a tumor and most likely one of the mutated cells has mutated further. Normally the body would destroy these cells if it notices problems in the genetic material but the mutation prevents the cell from self-distructing. By the time a fourth mutation had occured the new cells are able to push thier way through the epithelial tissue membrane and the cells are no longer contained, but unfortunatly the tumor is still to small to be detected and now the cells will be able to infect the rest of the body. This is done by a process calles __angiogensis__ when new blood vessels form on the tumor from the network of neighboring blood vesseles and when the tumor receives the blood and nutrients it grows faster. Its cells enter the blood stream where they can now travel to other parts of the body. If these cells surive after enetering the blood stream __metastasis__ will occur and this is when the cells establish new tumor sites throughout the body causing more and more damage. As you can see cancer is a very serious mutation and has a pround effect on the body. The best way you can prevent cancer is to advoid over exposure to toxins such as cigarettes and envorinmental toxins, UV rays, mantain a healthy weight, and exposure to carcinogens. __To further your understanding. . . . . . ____.__

Cell Cycle Information []

Mitosis Animation & Quiz <span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">[]

<span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">Cancer <span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">[]

__<span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">My works cited: __ <span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">Prentice Hall textbook (Chapter 10-2) <span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">Class Notes <span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">[|www.pbs.org] <span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">[|www.biologycorner.com] <span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">[|www.higherd.mcgraw-hil.com] <span style="color: #9600ff; font-family: 'Comic Sans MS',cursive; font-size: small;">[|www.biology.arizona.edu]