stem cells

• Stem cells


  Cells that can divide by mitosis to form more cells and can differentiate into specialized cells
• Human life starts


  1. Sperm cell fertilizes egg cell

  2. Forms a single cell called a zygote

  3. Zygote divides by mitosis over and over again

  4. Forms a small group of cells called an embryo
• Embryonic stem cells


  • Can differentiate into absolutely any type of cell (e.g. nerve, skin, blood)
• Adult stem cells


  • Can only differentiate into a narrow range of cells (e.g. different types of blood cells)
• Bone marrow


  Jelly-like substance in the middle of large bones that contains adult stem cells
• Plant stem cells


  • Found in plant tissues called meristems, which are areas of continuous growth
  • Can differentiate into all the cells and tissues the plant needs (e.g. palisade cells, phloem, xylem, root hair cells)
  • Persist for the plant's entire life, unlike embryonic stem cells
• Stem cells can divide by mitosis to form more cells
• Stem cells can differentiate into specialized cells
• Embryonic stem cells can differentiate into any cell type
• Adult stem cells can only differentiate into a narrow range of cells
• Plant stem cells are found in meristems and can differentiate into all plant cell types
• Plant stem cells persist for the plant's entire life