Biotechnology

1. Biotechnology

2. Profiling Techniques • DNA Profiling / Fingerprinting: DNA is cut, by special enzymes, at specific base sequences which will indefinitely vary from person to person. • These cut strands are then run through electrophoresis gel and can be compared with the DNA from other sources. If they match they are the same DNA. Genetic probes • Genetic probe/gene probe: a fragment of DNA or RNA labelled with radioactive isotopes / fluorescent markers to aid in the identification of specific squence of bases. • The fragment is added to the denatured DNA and if it combines then it will be identifiable in the chromosome later.

3. Polymerase chain reaction (PCR) • Segments of DNA are artificially multiplied using DNA polymerase (generally Taq polymerase from the Thermusaquaticus bacteria) and primers (which get process started) • DNA is denatured (by heat) so it splits • Then the primers are added which provides a starting point for the process (on both strands) • Polymerase causes reproduction of strand • The process continues on the products of the 1st PCR (more primer and polymerase are added each time) but the strand becomes more precise.

5. Genetic Engineering (Recombinant DNA Technology) • Introduction of foreign or modified DNA into an organism • Transgenic organisms: genome altered by additional genes • Generally the purpose in not to make copies of a gene but to give the vector the gene to produce something else (eg. Insulin or hGH) • Plasmids: are circular double stranded units of cytoplasmic DNA (can replicate in a cell independantly of chromosomal DNA) • Restriction enzyme: enzyme which cuts strands of DNA at specific nucleotide sequences (usually with ‘sticky ends’)

7. Insulin • Initially obtained from pancreas of pigs and cattle • hGH • Initially obtained from anterior pituitary gland of deceased people. • Factor VIII • Haemophilia is caused by a disorder in a blood clotting protein known as factor VIII • Factor VIII was originally obtained from the plasma of donors but as a result, infections of HIV and Hrp C were abundant. • Recombinant Factor 8 has solved many problems. • Vaccines • E.g Hep B vaccine

8. Gene Therapy • Replacement of a faulty gene with a healthy one • E.g. Cystic fiobrosis: • Affects mainly lungs and pancreas causing excess mucus production which may trap bacteria in the lungs causing infection.  lung damage, decreased lide expectancy • Also afects secretion of digestive enzymes • Mutations in CFTR gene (Cystic Firosistransmembrane regulator) cause Cystic fibrosis • By adding normal copies of gene the mutations don’t occur. (unfortunately when new cells die they are replaced by fautly ones- approx every 120 days) • Delivered by fat capsules, nose drops, synthetic vectors, possibly aerosol. • E.g. Huntingtons disease • Mutated protein (called huntingtin) results in brain nerve cells being damaged • Results in flailing limbs and eventual dmentia • Possible gene therapy to introduce a corrective gene which boosts a natural shield against effects of defective huntingtin.

9. Cell replacement therapy • The process of replacing defective cells with new stem cells Tissue Engineering • Process of restoring healthy organs by replacing defective tissues • The tissue is grown from stem cells which attach to a ‘scaffold’ (natural or artificial biodegradable, poreous, structure wich will allow tissue to form around it)