Mitosis

• What does mitosis produce?


  2 daughter cells that have the same number of chromosomes as the parent cell and each other
• What is the preparation for mitosis in relation to chromosomes?

  Before mitosis, each of the chromosomes is replicated.

  The two copies of each chromosome are called chromatids.

  The chromatids remain attached to each other at the centromere.
• What is the name of stage 1 of mitosis?


  prophase
• What happens during prophase?


  chromosomes become visible- appear as 2 chromatids joined at the centromere.

  The chromatids start to shorten as the DNA coils up tighter- this is called condensation, the chromatids are condensed.

  The membrane around the nucleus breaks down and the nucleolus disappears.

  A series of microtubules, which will form the spindle apparatus in mitosis, start to form and so become visible.
• What is stage 2 of mitosis called?


  Metaphase
• What happens during metaphase?


  Chromosomes are lined up in the middle of the cell.

  The spindle fibres are now clearly visible. Spindle fibres are a series of microtubules that organise the position and movement of chromatids during cell division.

  Spindle fibres are attached to the centromere.
• What is the 3rd stage of mitosis?


  Anaphase
• What happens during anaphase?


  The chromatids are attached to spindle fibres by their centromeres- where these fibres contract, the chromatids are pulled apart towards the poles of the cell.
• What is the 4th stage of mitosis called?


  Telophase
• What happens during telophase?


  The chromosomes reach their respective poles and become longer and thinner.

  Eventually the genetic material is only visible as chromatin.

  Nuclear membranes start to reform around each set of daughter chromosomes.

  Mitosis is now complete
• What happens after mitosis?


  cytokinesis
• What is cytokinesis?


  The process of 'cell splitting'.