Genetic manipulation

2.8.2 Genetic disorders

3.1 Photosynthesis

Genetic manipulation

  1. Cloning

    1. Tissue culture is the use of small groups of cells from part of a plant
    2. Embryo transplant is the use of stem cells from a developing animal embryo that are split apart and each identical embryo transplanted into host mothers

    3. Adult cell cloning

      1. The nucleus is removed from an unfertilised egg cell and the nucleus from an adult body cell inserted
      2. An electric shock acts as the catalyst for the egg cell to begin dividing to form embryo cells containing the same genetic information as the adult
      3. When the embryo has developed into a ball of cells, it is inserted into the womb of an adult femle to continue its development

    4. Concerns

      Advantages Disadvantages
      Cloning can save animals from extinction Concerns about the ethics of cloning
      Animal genetically engineered to produce valuable proteins in their milk for medicine can be cloned Cloning limits the gene pools, which can be a problem for natural selection if the environment changes
      Cloning cattle can produce herds of cattle with useful characteristics, especially preserving the best animals Concerns about using the technique to clone humans in the future

  2. Genetic engineering

    1. Genes from the chromosomes of organisms can be “cut out” and transferred to cells of other organisms
    2. Enzymes are used to isolate the required gene
    3. This gene is inserted into a vector, usually a bacterial plasmid or a virus
    4. The vector is used to insert the gene into the required cells

  3. Genetic modification

    1. Genes can also be transferred to the cells of organisms at an early stage in their development so that they develop with desired characteristics
    2. Crops that have had their genes modified like this are known as genetically modified GM crops

    3. Concerns

      Advantages Disadvantages
      If a person has a faulty gene, they have a genetic disorder, and if the correct gene can be transferred to the person, they could be cured Many people worry about the effect of eating GM crops on human health
      Several medical drugs have been produced by genetic engineering, such as insulin & antibodies Concerned about accidentally introducing genes into wild flower populations
      Genetically modified crops generally show increased yields Farmers have to buy new GM seed every year because crops are infertile
      Genetically modified crops can be resistant to insect attack or herbicides Insects that are not pests may be affected by GM crops