Cloning

• how can plants be cloned?

  • taking plant cuttings
  • tissue culture
• what is tissue culture?

  using small groups of cells from part of a plant to grow identical new plants
• describe how plants are grown using tissue culture

  1. select a plant showing desired characteristics
  2. cut multiple small sample pieces from meristem tissue
  3. grow in a petri dish containing growth medium
  4. transfer to compost for further growth
• what must be ensured when preparing tissue cultures?

  aseptic conditions to prevent contamination by microorganisms
• what does the growth medium contain?

  nutrients and growth hormones
• advantages of growing plants by tissue culture

  • fast and simple process
  • requires little space
  • enables growth of many plant clones with same desired characteristics
  • useful in preservation of endangered plant species
• disadvantages of growing plants by tissue culture

  • reduction in gene pool
  • plant clones often have a low survival rate
  • could unknowingly increase the presence of harmful recessive alleles
• brief overview of plant cuttings method of plant cloning

  • older but simpler method than tissue culture
  • gardeners use this method to produce many identical new plants from a parent plant
• detail the process of plant cuttings method of plant cloning

  1. branch is cut off from the parent plant
  2. lower leaves of the branch are removed and the stem is planted
  3. plant hormones are used to encourage new root development
  4. plastic bag covers the new plant to keep it warm and moist
  5. new roots and a new plant is formed after a few weeks
• what does embryo transplanting involve?

  • pre-specialised cells from a developing animal embryo are spilt apart
  • resulting separate but identical embryos are transplanted into host mothers
• describe how adult cell cloning is performed

  1. nucleus removed from unfertilised egg cell
  2. nucleus from adult body cell is inserted into the egg cell
  3. electric shock stimulates the nucleated egg to divide and it forms an embryo
  4. embryo cells contain the same genetic information as the adult body cell
  5. when the embryo is a ball of cells, inserted into the uterus to continue developing