CELL DIVISION BY MITOSIS

• • In the nucleus, there are chromosomes which are made of the molecule DNA
• • Body cells contain two of each chromosome, they are paired
• • Chromosomes carry large number of genes, which determine many of our features
• • Cells have to be able to divide, that is the cell cycle
• Stages of Cell Cycle

  • Stage 1 of cell cycle, DNA replicates itself to form two copies of each chromosome
  • The cell grows and copies its internal structure such as mitochondria and ribosomes
  • 2nd stage, mitosis takes place
  • One set of chromosome is pulled to each end of the cell, the nucleus also divides
  • 3rd stage (final stage) cytoplasm and cell membrane divide to form two identical cells
• Functions of mitosis

  1. Mitosis essential for growth and development of multicelluar organisms (e.g plants and animals)
  2. Mitosis takes place when an organism repairs itself (e.g when a broken bone heals itself)
  3. Mitosis happens during asexual reproduction