Biology: Mitosis, or Cell Division

Mitosis, or Cell division, happens (or occurs) when a cell goes through multiple stages, known as the cell cycle, and as the cell goes though each stage, the cell eventually divides and produces two identical daughter cells.

The main purpose of Mitosis (or Cell division) is to produce and grow cells that make the human body function properly. This organized process is highly essential for replacing old and worn out cells, tissue growth, development, and extremely important for tissue repair and loss of tissue caused by factors, such as diseases.

As mentioned earlier, the cell cycle is basically a series of stages, in which somatic cells go through and a replication of the somatic cell is produced. Additionally, the cell cycle has two basic and major phases (or stages) known as Interphase and Mitotic (M) phase. It also has an additional stage known as Cytokinesis.

Interphase is the stage where cells prepare themselves for cell division. There are three distinctive phases (stages) within the Interphase stage of the cell cycle. These three stages are known as G1, S, and G2. The G1 phase, also called the first gap stage, is where cells grow and produce more organelles, more proteins, and new structures required for the replication of DNA. Once all that happens, the somatic cells then go into the S phase. The S phase, also called synthesis, is where DNA is replicated. It starts off with 46 chromosomes (pieces of DNA) and ends up with 92 sister chromatids (identical pieces of DNA held together by a centromere). And finally, the last stage of Interphase is the G2 phase. The G2 phase, also called the second gap stage, is rather quicker than the other stages within the cell cycle.

During the G2 phase, cells continue to grow and make final preparations for mitosis (cell division). After Interphase, the cells then go through the Mitotic (M) phase of the cell cycle. According to the book, Anatomy and Physiology: An Integrative Approach, it states that, “Two distinct events occur in this phase to produce two new cells: Mitosis, which is division of the nucleus, and cytokinesis, which is the division of the cytoplasm. Mitosis begins first with cytokinesis starting and overlapping with later stages of mitosis” (McKinley 144).

To add on, the Mitotic (M) phase also has three distinctive stages called: Prophase, Metaphase, Anaphase, and Telophase. The first stage of mitosis is Prophase. During prophase, chromatin starts to condense and coil into chromosomes. Mitotic spindle fibers start to form from the centrioles. Centrioles will then pull apart and separate to opposite ends of the cell. At the end of prophase, the chromosomes finish condensing and become very visible and both the nuclear envelope and nucleolus break down and disappear. The second stage of mitosis is Metaphase.

During this stage, spindle fibers begin to connect to chromosomes at the centromere and the chromosomes will then line up in a straight line on the metaphase plate region of the cell. The third stage of mitosis is Anaphase. In the article, Mitosis, the writer J. Richard McIntosh, describes anaphase as, “the separation of each chromosome into two identical parts, followed by their movement toward the opposite ends of the cell.” In other words, the “glue” holding the sister chromatids together breaks down and chromosomes of each pair are separated and then pulled towards the opposite ends of the cell. The fourth stage of mitosis is Telophase.

Here chromosomes begin to decondense and return to stringy form of chromatin, a nucleolus reforms from each new nucleus from two individual cells,  the mitotic spindle fibers will break up and disappear,  and finally new nuclear envelopes form around each pair of chromosomes. Lastly, Cytokinesis is the last and final event of mitosis. Cytokinesis, as mentioned earlier, is the division of the cytoplasm and it begins during late anaphase and continues through telophase. When cleavage furrow appears during cytokinesis, usually that points where the cytoplasm is being divided and two new daughter cells are formed, which then results in the completion of mitosis (cell division).

Cancer

Tochtli, the main character and narrator in the novel, in my opinion is a static character. Tochtli does not go through a dramatic change in the book; yes, he cried towards the end of the book, but that isn’t a dramatic change of character. The reason why I think Tochtli is a static character is because he was basically the same person (character) throughout the novel. He was a young boy who was demanding and absorbing violence. While explaining how solidarity his family’s “gang” is and how his father, Yolcaut, buys him hats, Tochtli states, “Although now more than new hats what I want is a Liberian pygmy hippopotamus. I’ve already written it down on the list of things I want and given it to Miztli” (Villalobos 5).

Here it supports why Tochtli is demanding throughout the book because Tochtli is that one kid who asks for things because he feels like it. Yes, he is a young child and young children do tend to ask for things when it’s unnecessary, but throughout the book Tochtli is consistent when asking his father for new things. For example, Tochtli’s number one wish was to get a Liberian pygmy hippopotamus and he gets mad or should I say “mute” when his father keeps telling him that he’ll get it for him later, which he ultimately does. Not to mention, towards the end of the book he wants a Samurai sword, but he knows that his father wouldn’t allow him to have a Samurai sword, so he secretly tells Miztli to get him a Samurai sword.

Another reason why Tochtli is a static character is because he is into violence. There are scenes where Tochtli is continuously seeing violence on television which causes him to absorb the violence going on around him and his town. Tochtli mentions, “Since then there’ve been corpses on the TV every day” (Villalobos 23).

Tochtli does not know better, but to believe what he sees on tv. Even before he sees all the violence going on from his own tv, he was already fantasized by the French and how the French used to cut off people’s heads with a guillotine. Not to mention, he also sees violence in his own home. There were scenes where Tochtli sees a man getting viciously beat by the palace guards and he also sees dead people getting eaten by his pets (two tigers and one lion).

There’s also another scene where Tochtli displays his absorption of violence. He was playing around with a gun and he ends up shooting and killing a lovebird. His first initial reaction was throwing the gun away because he didn’t know what was going to happen afterwards. This was basically his very first act of violence towards a living thing and he acted totally normal and he seem not to care at all.

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