ch 10 Flashcards
what does genetic engineering involve?
Genetic engineering involves building recombinant DNA, a molecule made from pieces of DNA from separate organisms.
the four basic steps of genetic engineering:
cleaving DNA, producing recombinant DNA, cloning cells, and screening cells.
restriction enzymes
Restriction enzymes recognize specific nucleotide sequences and cleave DNA into fragments. DNA molecules cleaved by the same restriction enzyme will have complementary ends which allow DNA fragments from different organisms to join.
what is the southern blot technique?
The Southern blot technique is used to screen clones to determine whether they contain specific recombinant genes.
what is RFLP analysis based on?
RFLP analysis is based on the fact that restriction enzymes cut DNA into fragments that have specific lengths.
what does the polymerase chain reaction allow scientists to do?
The polymerase chain reaction allows scientists to produce millions of copies of DNA in just a few hours.
what was the goal of the human genome project?
The Human Genome Project is a research effort to identify and locate human genes.
what is genetic engineering used for?
Genetic engineering techniques are being used to manufacture proteins such as insulin and factor VIII, as well as vaccines.
how can some human genetic disorders be treated with genetic engineering?
Some human genetic disorders are being treated and “corrected” by inserting copies of the corresponding normal gene into individuals whose copy of the gene is defective.
how can genetic engineering also be helpful to humans in other ways (than in the human body)?
Genetic engineers have manipulated the genes of certain kinds of crop plants to make them resistant to herbicides and destructive pests.
what are genetic engineers still looking for to help plants?
Genetic engineers are looking for ways to transfer genes for nitrogen fixation from bacteria into crop plants.
how else can genetic engineering also help humans without genetically engineering humans or plants?
The addition of genetically engineered growth hormone to the diets of livestock increases milk production in dairy cows and weight gain in cattle and hogs.
Genetic Engineering
transferring gene from DNA of one organism to another.
Recombinant DNA
molecule made from DNA of two different organisms.
Cohen & Boyer technique:
- Cleaving DNA – cutting gene out of source DNA with a restriction enzyme. The restriction enzyme cuts frog DNA at specific sequences. Cohen & Boyer isolated gene they wanted in frog fragments and obtained a plasmid they wanted (which has replication and tetracycline resistance genes).
- Producing recombinant DNA – cut vector molecule (plasmid or virus) with same restriction enzyme. (Vector – agent used to carry substance into something) Add selected gene fragments which will be inserted into vector because both have complementary “sticky” end.
NOTE: Plasmids are small circular DNA molecules that are found in bacteria that can be exchanged from one bacteria to another so useful genes can be shared/propagated within one generation - horizontal gene transfer. This helps deal with the problem of less chance for diversity because bacteria reproduce asexually and the only way the daughter cells might be different from the parents is by random (and rare) mutation
- Temperature Shock – introduce vector into destination bacteria culture and encourage the bacteria to take it in – only some of which will by having bateria tube go from cold to hot and then back to cold.
- Cloning & Screening cells – isolating bacteria that have been transformed (plate with an antibiotic) and clone them (let them reproduce) on a plate. The replication gene ensures all the daughter cells (clones) have the replicated plasmid and the tetracycline resistance gene ensures that only the bacteria that took in the plasmid can grow.
