Student Publishing Program ::

Xiubo F.

To Mitosis, Without Which I Would Not Be Possible As A Multicelluar Eukaryotic Organism

As eukaryotic organisms grow,
The functioning cells that they are composed of need to increase,
And the process that accomplishes this is part of the cell cycle.

Picture the cell as a soap bubble,
And the growth of a eukaryotic organism from cell number increase,
Is like a structure made of bubbles getting larger,
By adding more bubbles to the structure.

It is called cell division,
In this context mitosis.
Although there is another kind called meiosis.

Cell division is analogous to copying a bubble through splitting the bubble.

Mitosis makes a copy of the original bubble by spliting the bubble,
Into two identical bubbles the same size as the original.
And meiosis splits the original,
Into two identical ones that each have half the content of the bubble.

The other part of the cycle of the cell is interphase.
It is divided into three subphases,
Called G₁ phase, S phase, and G₂ phase.

There is a similarity between all three subphases of interphase.
It is that the cell make cytoplasmic organelles and proteins,
And thus the cell grows sometimes by the day.

The cell cycle all starts with G₁ phase,
One of the subphases where the cell is in growth,
And where the adenosine triphosphates can be used sometimes for many days.

Next comes S phase,
Where chromosome duplication takes place,
And the product is made of chromatin fibers in a compact arrangement to save space.

S phase is when the content of the bubble double,
And the contents are tightly grouped together inside the bubble.

Then comes G₂ phase,
Very similar to G₁ phase,
With a major difference that it is the last subphase of interphase.

G₂ phase is like a time where the volume of the bubble continue to increase,
And the bubble reaches its biggest volume at the end of this phase.

Interphase is explained here in this detail because it is 90% of the cell cycle,
And because it is something that mitosis and meiosis have that are identical.

Now back to mitosis,
Which is also divided into subphases,
Called prophase, prometaphase, metaphase, anaphase and telephase,
And perhapes cytokinesis.

Mitosis starts with prophase,
Where the nucleoli is no longer visible,
And where microtubules move the centrosomes away from their original place.

The chromosomes,
Now pairs of sister chromatids that are identical and attached at the centromere,
Condense but are still separated from the centrosomes.

During prometaphase,
The nuclear envelope breaks.

Some attach to the kinetochore of the chromosomes,
Others affect microtubles from the opposite pole of the cell,
Although all microtubles extend toward the cell center from the centrosomes.

At metaphase,
The centromeres,
(containing the previously mentioned kinetochores),
Of the chromosomes line up at the metaphase plate,
And then begins anaphase.

Where sister chromatids separate at the centromere and become daughter chromosomes,
Because the pairs of microtubules attached to the chromosome kinetochores shorten,
And daughter chromosomes move toward their microtubles’ centrosomes.

The last subphase of mitosis is telephase.
Where each of the two sets of identical chromosomes,
Have a nuclear membrane formed around them,
Which is different from what happens in interphase.

Cytokinesis is the last step in making an identical cell,
Where the cell splits at the cleavage furrow in this context,
And two identical cells are formed when cytokinesis is done well.

Mitosis is interesting because it helps explain nature,
And thus can be used to make things better.

Moreover mitosis helps us appreciate the work of our cells,
Which is all done to help us and make us ourselves.

It should be noted that parts of the cell cycle like mitosis have some complexity,
And yet cells go through it with almost perfect accuracy.

Therefore, remember to accomplish and stay well,
In appreciation of the work,
And the professionalism of each of your cells.

[TABLE OF CONTENTS, LHS CLASS OF 2009 EDITION]