Cell Division

• Unicellular cell division is for the purpose of reproduction, while multicellular cell division is for the purposes of growth and repair.
• The function of the nucleus is to control all a cell’s activities. The nucleus contains genetic information in the form of genes on chromosomes which are made of DNA.
• In humans, all normal body cells contain 46 chromosomes. The 46 chromosomes are made

  up of 2 matching sets of chromosomes forming 23 pairs of chromosomes.
• In each pair, 1 chromosome came from mum and the other came from dad. Cells which have a double set of chromosome, like human body cells, are known as DIPLOID.
• A chromatid is a single strand which is part of a

  chromosome when the chromosome has 2 strands.
• Each species has a specific and characteristic number of chromosomes within each cell. This is known as the chromosome complement. Since chromosomes provide the genetic information for each species, it is essential that each new cell receives a full complement of chromosomes.

  This ensures that animals and plants are provided with all the characteristics of their species.
• Uncontrolled Cell Division

  
  

  -Cancer is a disease that starts in our own cells.

  
  

  -A change in the DNA causes a special gene called an oncogene to be switched on.

  
  

  -This leads to uncontrollable cell reproduction by mitosis. This is cancer.