Mitosis

Mitosis 

For A level you will be required to remember the main stages;

Intaphase (THIS IS NOT A STAGE)

G1-This is the stage of the cell cycle before mitosis by where the cells carries out its normal activities, it is the longest stage.

Synthesis stage- DNA is synthesised 

G2- Cells have duplicated and in the form chromatin 

     - Centrioles are replicated 

Prophase

During this phase chromosomes thicken and condense and become visible and are seen as two sister chromatids joined at the centre by a centromere 

Centrioles migrate to opposite poles of the cell

Nuclear envelope disintegrates  

Spindle fibres begin to form 

Metaphase 

During this stage sister chromatids line up at the centre of the cell (metaphase plate)

Spindle fibres join at the centromere of the chromosome 

Anaphase

Spindle fibres break the centromere joining the chromosomes and sister chromatids seperate and move to opposite poles of the cell  

Telophase 

Chromosomes begin to unwind and become chromatin 

Nuclear envelope reforms along with the nucleolus 

IMPORTANT TO REMEMBER THAT TWO GENETICALLY IDENTICAL DAUGHTER CELLS ARE FORMED EACH WITH 23 PAIRS OF CHROMOSOMES