stem cells

• two types of stem cells found in animals:

  • adult stem cells
  • embryonic stem cells
• two key features of stem cells:

  • they can divide by mitosis
  • they can differentiate into specialised cells
• when a sperm cell fertilises an egg cell they form a single cell called a zygote

  This cell then divides by mitosis to form a ball of cells which we call an embryo

  The cells in this embryo are known as embryonic stem cells and can differentiate into any type of cell
• Can adult stem cells divide by mitosis

  • yes
• adult stem cells can only differentiate into different types of blood cells such as white blood cell and red blood cells
• adult stem cells are found in bone marrow
• meristems are plant tissues that are continually growing and contain stem cells
• Two parts of the plant that contain meristem tissue

  • tips of shoots
  • tips of roots