Human Biology - Genetics

OCR Human Biology Unit 5

  • Created by: Freya
  • Created on: 28-04-14 14:13
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  • Genetic Techniques
    • Genetic Engineering
      • Restriction Enzymes used to cut up and join together parts of DNA of one organism and insert them into another organism
        • Restriction enzymes = Restriction endonucleases
          • Some cut to form blunt ends, but sticky ends are most useful
            • Sticky ends form hydrogen bonds to complementary base pairs = the two pieces have annealed
          • Cut DNA at palindromic sequences = same in both directions
        • After being cut broken DNA is repaired using DNA ligases
      • Genetic engineering = changing the DNA code in a living organism
      • Vector = a length of DNA that carries the gene into a host cell
        • A bacterial plasmid is often used as a vector
      • Marker genes inserted into recombinant DNA
        • Makes it easy to find which organisms have been successfully engineered
      • When using eukaryotic cells in animals product must be in milk or urine
        • AAT - human protein that inhibits protease enzymes like elastin
          • Genetically engineered AAT can by produced in sheep and used to treat emphysema
    • DNA profiling
      • Gel Electrophoresis
        • Form of chromotography
        • Used to seperate different pieces of DNA based on their length
        • DNA fragments stained with a chemical e.g. azure A
      • Form of genetic fingerprinting
      • Polymerase Chain Reaction
        • Used to replicate DNA
        • High temperature used to seperate DNA molecules into single strands = denaturation
      • Involves identifying patterns of genetic material
      • Used in forensic science, paternity testing, matching organ donors
    • Human genome project
      • Project devised to map and sequence the entire human genome
      • Fuelled the discovery of more than 1800 diseases
      • Now more than 1000 tests for genetic conditions
      • Problems raised - should insurance companies be allowed to see results of genetic tests
    • Genetic Counselling
      • Genetic counsellors work with people concerned about the risk of an inherited disease
      • Helps people to understand the nature of a disease and what having it will mean
      • Ethics - questions about abortion, counsellors learn a lot of family secrets (e.g. false paternity)


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