Commission: Cell Cycle Summary

This is a simplified summary of the Cell Cycle that I've written up simply so its easier for me to weave this information into a narrative. Its by no means a script, but it gives me something to work with.

Introduction

The Human Body is made up of around fifty trillion little building blocks called Cells.

These Cells are called upon whenever the body undergoes particular genetic changes, such as when your hair grows or when you cut yourself.

But, where exactly do all these Cells come from?

Cells duplicate and divide themselves through Mitosis, a process that occurs whenever Cells are needed to fulfil a particular task.

A Cell goes through many stages before it finally divides into two.

The Interphase

The process begins with the Interphase. The Interphase is broken into three sub-phases.

The first is the G1 phase. During this phase, the Cell grows in preparation for Mitosis and functions as normal.

This leads into the S phase, where the DNA produces two copies of each chromosome.

The final phase is the G2 phase, in which, much like the G1 phase, the Cell’s preparations for Mitosis continue.

The Mitotic Phase

Once the Interphase has passed, the Cell moves into the Mitotic phase.

Like the Interphase, the Mitotic phase has several sub-phases. 

First of all is the Prophase, where the chromosomes coil up and condense, making them shorter and thicker, and the nuclear envelope containing them is broken down. The separate copies of a single chromosome are known as sister chromatids. Spindle fibres are formed whilst centrioles move to either end of the Cell.

The next step is the Metaphase. The chromosomes line up in the centre of the Cell. Microtubules formed during the Prophase attach to the sister chromatids. 

The sister chromatids begin to separate, this is the beginning of the Anaphase. The sister chromatids are held together by the centromere, which begins to divide as each sister chromatid, moves down its spindle fibre.

The final step is the Telophase, in which the two now separate groups of chromosomes reaching opposing sides of the Cell. Both groups gain a new nuclear envelope and the chromosomes uncoil.

Cytokinesis

After the Mitotic phase comes Cytokinesis, where the cytoplasm and organelles divide.

The completed process of Mitosis and Cytokinesis result in two separate cells that are genetically identical. The resulting Cells are known as daughter Cells.