Cambridge (CIE) AS Your notes
Biology
Chromosome Behaviour in Mitosis
Contents
The Stages of Mitosis
Observing Mitosis
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, The Stages of Mitosis
Your notes
Mitosis: The Stages
Mitosis is 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)
Although mitosis is, in reality, one continuous process, it can be divided into four main
stages
These stages are:
Prophase
Metaphase
Anaphase
Telophase
Most organisms contain many chromosomes in the nuclei of their cells (e.g. humans have
46) but the diagrams below show mitosis of an animal cell with only four chromosomes,
for the sake of simplicity
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 chromosomes consist of two identical chromatids called sister chromatids (each
containing one DNA molecule) that are joined together at the centromere
The two centrosomes (replicated in the G2 phase just before prophase) move towards
opposite poles (opposite ends of the nucleus)
Spindle fibres (protein microtubules) begin to emerge from the centrosomes (consists
of two centrioles in animal cells)
The nuclear envelope (nuclear membrane) breaks down into small vesicles
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Biology
Chromosome Behaviour in Mitosis
Contents
The Stages of Mitosis
Observing Mitosis
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 1
, The Stages of Mitosis
Your notes
Mitosis: The Stages
Mitosis is 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)
Although mitosis is, in reality, one continuous process, it can be divided into four main
stages
These stages are:
Prophase
Metaphase
Anaphase
Telophase
Most organisms contain many chromosomes in the nuclei of their cells (e.g. humans have
46) but the diagrams below show mitosis of an animal cell with only four chromosomes,
for the sake of simplicity
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 chromosomes consist of two identical chromatids called sister chromatids (each
containing one DNA molecule) that are joined together at the centromere
The two centrosomes (replicated in the G2 phase just before prophase) move towards
opposite poles (opposite ends of the nucleus)
Spindle fibres (protein microtubules) begin to emerge from the centrosomes (consists
of two centrioles in animal cells)
The nuclear envelope (nuclear membrane) breaks down into small vesicles
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