genetics

• a gene is a heritable factor that consists of a length of DNA and influences a specific characteristics
• Alleles are different versions of the same gene.
• in eukaryotes chromosomes occur as homologous pairs- cells that have two copies of each gene
• genome is the whole genetic material of an organism

  • genome size is not an indicator of an organisms complexity
• Mutations are a change in the sequence of base pairs in a DNA molecule- sometimes leads to a change in the coded protein
• Sickle cell anaemia occurs from a single base substitution in the beta-globin gene where adenine is replaced by thymine
• gel electrophoresis:

  • separation of proteins and DNA fragments according to size and charge
• PCR

  • used to amplify a single piece of DNA and make many copies
  • denaturing, annealing, extension
• DNA profiling- identifying and comparing individuals based on their DNA base sequence
• PCR- to increase quantity of DNA

  • denature, anneal, elongate

  Cut DNA with restriction enzyme

  • cut outside short tandem repeat regions
  • creates fragments of different sizes

  Gel electrophoresis- separate the DNA fragments

  DNA profiling- transfer from gel to membrane
• transgenic organisms- organisms that have been genetically modified to produce a desired trait
• Insulin synthesis:

  • insulin gene taken from human cell
  • plasmid take from bacteria
  • sticky ends of gene create recombinant plasmid
  • this creates a transgenic bacteria
  • this is grown in a culture
  • insulin can then be extracted