1.6 Biotechnology 2.

• Genetic Engineering


  The process of combining DNA from two different origins to produce 'recombinant DNA', this creates genetically modified organism (GMO) or transgenic organisms
• Transgenic


  1. Extract DNA from cells

  2. Select/locate the target DNA sequence using a gene probe

  3. Remove DNA segment of interest- either done using restriction enzymes or CRISPR

  4. Transfer DNA into host organism using either micro injection, viral vectors, bacterial plasmid vectors, electroporation, or bacterial transformation

  5. DNA ligase binds new DNA with host DNA
• Micro injection


  • Injecting new DNA into a host cell nucleus using a micro needle
  • Usually done on eukaryotic cells as they are larger
  • DNA ligase is not added as it is already present in the host cell
• Bacterial plasmid vector


  • Inserting a target gene into a bacterial plasmid which is then inserted into a host cell
  • The plasmid then inserts the DNA into the host organism's DNA
  • The same restriction enzyme that was used to cut out the target gene is used to cut the bacterial plasmid DNA as it has the same sequence
• Viral vectors


  • Pathogenic DNA is removed from virus and target DNA is inserted
  • Virus infects host cells and inserted target DNA into genome
  • Infected cells are then inserted into the host organism
• Electroporation and bacterial transformation

  • Using electricity to create small pores in the cell membrane to allow target DNA to enter cells
  • Bacterial transformation is the same but in bacteria cells to allow entry of modified plasmid through the membrane
• Use of yeast for genetic engineering


  • Yeast is a eukaryotic- research on yeast cells is translatable to human cells
  • Yeast reproduces rapidly and cultures easily
  • Yeast cells contain plasmids (like prokaryotic cells) so they are easy to manipulate
• Synthetic proteins


  • Creating a synthetic gene to code for a specific protein
  • Requires attention to detail- remember protein folding and shape is determined by amino acid sequence which is determined by the DNA sequence
• Uses of synthetic proteins

  • Vaccine development
  • Proteins that change colour when bonded to certain molecules to act as markers
  • Modifying channel proteins in the cell membrane to increase uptake of certain molecules
• CRISPR


  • Clustered regularly interspaced short palindromic repeats
  • Naturally occurring in bacteria and is how they protect themselves from viruses
  • The cas-9 or CRISPR associated protein 9 is able to be programmed so that it cuts DNA at specific locations
  • More specific and reliable than restriction enzymes
  • Has revolutionised genetic engineering processes
• How CRISPR works in bacteria

  1. Virus infects bacteria, bacteria stores viral DNA within CRISPR regions of its own DNA

  2. If same virus infects bacteria again, the bacteria makes an RNA copy of stored viral DNA and makes and enzyme (cas-9) which attacks and destroys invading viruses