Cell division and reproduction

• Replace


  To take the place of something
• What is meant by Cell division


  The process by which a cell divides into two or more cells
• Types of cell division

  • Mitosis
  • Meiosis
• Mitosis

  • Results in identical daughter cells
• Meiosis


  • Produces gametes that are genetically different from each other
• Cell cycle


  1. Stage 1: Cell growth and DNA replication

  2. Stage 2: Mitosis - Chromosomes pulled to ends, nucleus divides

  3. Stage 3: Cytoplasm and cell membranes divide into two identical cells
• Cell division by mitosis is important in the growth and development of multicellular organisms
• Meiosis


  • Halves the number of chromosomes while forming the gametes
  • Fertilisation restores the full number of chromosomes
• Meiosis


  1. Copies of genetic information are made

  2. Cell divides twice to form four gametes, each with a single set of chromosomes

  3. All gametes are genetically different from each other
• In sexual reproduction the mixing of genetic information leads to variety in the offspring
• Asexual reproduction involves only one parent and no fusion of gametes, leading to genetically identical offspring (clones)
• Benign tumour


  Growth of abnormal cells contained in one area, do not invade other parts of the body
• Malignant tumour


  Cancer cells that can invade neighbouring tissues and spread to other parts of the body