Outline the key stages that occur in mitosis.

The initial stage of mitosis is known as prophase. In early prophase, the nuclear membrane breaks down and the nucleolus disappears. The chromatin condenses into a doubled armed chromosome- comprised of two genetically identical sister chromatids. The centrosomes, organelles responsible for the separation of the two sister chromatids via the organisation of microtubules, migrate to opposite poles of the cell as the microtubules begin to radiate from them. Next is prometaphase, which is also known as late prophase. This is where the condensed chromosomes migrate towards the equator of the cell, known as the metaphase plate. The growing microtubules attach to the kinetochore, a complex of proteins attached to the centromere- a structure joining the two sister chromatids. Thirdly is metaphase. Here, the chromosomes align on the metaphase plate ready to divide. Anaphase follows metaphase by where the microtubules depolymerise (shorten) due to their filamentous properties, pulling the sister chromatids to opposite poles of the cell. Next is telophase. This is considered as the reverse of prophase. The nuclear membrane reforms and the nucleolus reappears. The microtubules disintegrate whilst the daughter chromosomes uncoil and become diffuse. Finally, the process of cytokinesis takes place by where the cell constricts outside inwards at the cleave furrow. This is where the cytoplasm divides to create the finished products- two new genetically identical daughter cells.