Cells - GCSE

• Stem cells


  Cells that can divide by mitosis to form more cells and can differentiate into specialized cells
• Stem cells


  • Can divide by mitosis to form more cells
  • 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

  5. Embryonic stem cells can differentiate into any type of cell
• Embryonic stem cells


  Stem cells found in the embryo that can differentiate into any type of cell
• Adult stem cells


  Stem cells found in adults that can only differentiate into a narrow range of cells
• Adult stem cells


  • Stem cells found in bone marrow that can differentiate into different types of blood cells
• Plant stem cells


  Stem cells found in plant tissues called meristems that can differentiate into all the cells and tissues the plant needs
• Plant stem cells persist for the plant's entire life, unlike embryonic stem cells which disappear by the time we're fully developed
• Cells


  The basic building blocks of life that can replicate independently
• Multicellular organisms like animals and plants contain many cells that divide to grow or replace dead cells, not to create new organisms</b>
• Bacteria are single-celled prokaryotic organisms
• Subcellular structures common to animal and plant cells


  • Cell membrane
  • Nucleus
  • Cytoplasm
  • Mitochondria
  • Ribosomes
• Plant cells


  • Have a rigid cell wall made of cellulose
  • Contain a permanent vacuole with cell sap
  • Contain chloroplasts for photosynthesis
• Bacterial cells


  • Lack mitochondria and chloroplasts
  • Have a single circular strand of DNA instead of a nucleus
  • May have additional plasmids
  • May have flagella for movement
• Bacteria are unicellular organisms, each individual cell is a whole organism
• Photosynthesis occurs in the chloroplasts of plant cells, using chlorophyll to absorb light energy
• Mitochondria in cells break down glucose through aerobic respiration to provide energy