Biotechnolog y

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.

Polymerase chain reaction (PCR) Segments of DNA are artificially multiplied using DNA polymerase (generally Taq polymerase from the Thermus aquaticus 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 1 st PCR (more primer and polymerase are added each time) but the strand becomes more precise.

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’)

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

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 Firosis transmembrane 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.

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)