The process of nuclear division by which two genetically identical daughter nuclei are produced that are also genetically identical to the parent cell nucleus (they have the same number of chromosomes as the parent cell)
Mitosis is, in reality, one continuous process, but it can be divided into four main stages
Chromosomes
Consist of two identical chromatids called sister chromatids (each containing one DNA molecule) that are joined together at the centromere
The different colours of the chromosomes are just to show that half are from the female parent and half from the male parent
Prophase
Chromosomes condense and are now visible when stained
The two centrosomes (replicated in the G2 phase just before prophase) move towards opposite poles
Spindle fibres (protein microtubules) begin to emerge from the centrosomes
The nuclear envelope (nuclear membrane) breaks down into small vesicles
The nucleolus disappears
Metaphase
Chromosomes line up at the equator of the spindle (also known as the metaphase plate) so they are equidistant to the two centrosome poles
Spindle fibres (protein microtubules) reach the chromosomes and attach to the centromeres
Each sister chromatid is attached to a spindle fibre originating from opposite poles
Anaphase
The sister chromatids separate at the centromere (the centromere divides in two)
Spindle fibres (protein microtubules) begin to shorten
The separated sister chromatids (now called chromosomes) are pulled to opposite poles by the spindle fibres (protein microtubules)
Telophase
Chromosomes arrive at opposite poles and begin to decondense
Nuclear envelopes (nuclear membranes) begin to reform around each set of chromosomes