cloning

• Scientists produce large numbers of genetically identical plants with desirable characteristics using micropropagation.
• Stage 1: Explants, which are small pieces of a plant or small pieces of plant

  tissue, are cut from a plant.

  Stage 2: Explants are sterilised with bleach, chlorine, ethanol, radiation (uv,

  gamma rays, x-rays)

  Stage 3: Explants are grown in sterile agar/jelly medium with nutrients

  (amino acids, glucose, nitrate).

  Stage 4: Agar plate is incubated and explants grow into calluses. Temperature, light and humidity/moisture need to be controlled.

  Stage 5: Small plants are grown in a glasshouse before being planted outside.
• advantages of using micropropagation

  1. Micropropagation produces many plants.

  2. Micropropagation is a quicker method.

  3. Micropropagation can be done at any time of the year.

  4. Micropropagation produces clones (genetically identical organisms).
• Process of cloning an adult animal using a named example (Dolly the sheep, Siberian tiger, a mammoth, etc.)

  1. Nucleus taken from a body cell of an adult cow (adult Syberian tiger, adult monkey, etc.)

  2. Nucleus put into an enucleated egg cell

  3. Egg cell given a mild electric shock to help it divide by mitosis

  4. Ball of cells called an embryo produced

  5. Embryo placed into the uterus of a female cow (surrogate mother)

  6. For extinct animals, appropriate similar species should be chosen as surrogate mother
• Advantages of using embryo cloning rather than using selective breeding to produce animals with desirable characteristics

  • Cloning produces more individuals
  • Cloning is a faster process
  • The clones are genetically identical
  • No need for mating (no gametes involved, no need for two parents)
• Advantages of using cloned organisms to provide organs rather than relying on people to donate organs


  • Cloning can produce lots of organs (No shortage, better supply)
  • Cloned organs would be accepted by the body (No rejection)
  • Cloning would avoid problems with relatives
• Disadvantages: Ethical issues