Cell division by Mitosis

• In the nucleus we find chromosomes which are made of the molecule DNA
• Body cells contain two of each chromosome. They are paired
• Human body cells contain 23 pairs of chromosomes
• Gametes have chromosomes which are not paired (ie human gametes have 23 single chromosomes)
• Chromosomes carry a large number of genes which determine many of our features
• Cell cycle (Mitosis)

  1. DNA replicates to form two copies of each chromosome
  2. Cell grows and copies internal structures
  3. Mitosis takes place - One set of chromosomes are pulled to each end of the cell. The nucleus also divides
  4. The cytoplasm and cell membrane divide to form two identical cells (Daughter cells)
• Functions of mitosis

  1. Essential for growth and development
  2. Mitosis takes place when an organism repairs itself
  3. Mitosis happens during asexual reproduction