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• Adult stem cell


  Undifferentiated cell that can develop into one or more types of specialised cell
• Binary fission


  Cell division in bacteria
• Cell cycle


  Series of stages that body cells go through to divide and form two identical daughter cells
• Chromosome


  Contains a large number of genes made of DNA molecules
• Clone


  Genetically identical copy of an organism
• Daughter cells


  Two identical cells formed by cell division
• Embryonic stem cell


  Stem cell from an early human embryo that can differentiate into any specialised cell type
• Gene


  Unit of heredity located on a chromosome
• Meristem


  Region of rapid cell division in the tips of plant roots and shoots
• Mitosis


  Cell division process that produces two genetically identical daughter cells
• Nucleus


  Contains the chromosomes in a cell
• Therapeutic cloning


  Using a patient's own cells to create an early embryo clone, then using stem cells from the embryo to treat the patient's medical conditions
• Adult stem cells


  • Found in specific parts of the body in adults and children
  • Can only differentiate into certain types of specialised cells
• Embryonic stem cells


  • Found in early human embryos
  • Can differentiate into any type of specialised cell
• Plant meristems


  • Found in the tips of plant roots and shoots
  • Can differentiate into all plant cell types
  • Used to clone whole plants
• Advantages of adult stem cells

  • Fewer ethical issues as adults can consent
  • Established technique for treating diseases like leukaemia
  • Relatively safe, donors recover quickly
• Disadvantages of adult stem cells

  • Require a donor, long wait times
  • Can only differentiate into certain specialised cell types
• Advantages of embryonic stem cells

  • Can treat a wide range of diseases
  • May be able to grow whole replacement organs
  • Usually no donor needed
• Disadvantages of embryonic stem cells

  • Ethical issues as embryo is destroyed
  • Risk of transferring viral infections
  • Relatively under-researched
• Advantages of using plant meristems to clone plants

  • Rare species can be cloned to prevent extinction
  • Plants with desirable traits can be cloned
• Disadvantage of using plant meristems to clone plants


  • Cloned plants are genetically identical, so whole crop at risk from single disease or defect
• Cell cycle


  1. Cell grows bigger

  2. DNA replicates (chromosomes duplicated)

  3. Mitosis - chromosomes pulled to each end, nucleus divides

  4. Cytoplasm and cell membrane divide to form two daughter cells
• Binary fission


  Cell division in bacteria, can occur every 20 minutes in optimum conditions
• Therapeutic cloning


  1. Patient's cells used to create early embryo clone

  2. Stem cells from embryo used to treat patient's medical conditions
• Chromosomes are made of DNA molecules
• In normal body cells, chromosomes are found in pairs
• Mitosis is used for growth, repair, and asexual reproduction
• The lid of a petri dish for bacterial growth must allow oxygen in but prevent harmful anaerobic bacteria from growing