What is mitosis?
Mitosis is a process whereby the chromosomes (which carry the genetic information) of the cell that were duplicated during replication,to make two identical set of chromosomes, are separated into two nuclei. This process is divided into four different stages:
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Prophase: during this stage the chromosomes condense and the DNA supercoils. The centrioles move to oppposite sides of the cell and form the microtubule spindle fibres. The latter form a bridge-like structure between the ends of the cell. The nucleus also dissolves and the nuclear membrane breaks down.
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Metaphase: the spindle fibres formed, connect to the centromere of each chromosome (which holds the sister chromatids together). The microtubules undergo depolymerisation and the spindle fibres shorten and contract, in this way the chromosomes align at the centre of the cell.
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Anaphase: during this stage the sister chromatids split apart due to the contractions of the spindle fibres and move to the opposite poles of the cell.
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Telophase: the spindle fibres dissolve once the two sets of chromosomes move to opposite poles and the chromosomes decondense. The nuclear membrane reforms around each set of chromosomes and the preparation for cytokinesis occurs, during which the cell is split into two.
