Genetic modification and biotechnology sl Flashcards
Where is DNA profiling commonly used?
Criminal investigations
Paternity tests
Outline what PCR is and when it is useful
PCR is a way of producing large quantities of a specific target sequence of DNA.
It is useful when only a small amount of DNA is available for testing.
It is used in DNA profiling
Outline what Gel electrophoresis is and what it is used for
Gel electrophoresis is a procedure that separates proteins of DNA fragments according to size. It is used in the analysis of DNA, RNA, and proteins.
PCR is used first to increase the number of DNA molecules
Outline the method of gel electrophoresis in detail:
An agarose gel plate is created in a tank
Wells (series of small rectangles) are cut into the gel on one end
The gel is submerged in an electrolyte solution in the tank
Insert DNA fragments through wells using micropipette
Apply electrical current to tank, the cathode providing a negative charge is connected on the wells’ side by the DNA and the positive charge anode on the other side.
This allows the DNA with the negatively charged phosphate group to be attracted to the opposite positive charge
DNA fragments with a smaller mass will move faster and further across tank
Fragments are not visible so are transferred to absorbent paper or nitrocellulose
Probes are then added to produce visual output.
What are the 3 stages of PCR per cycle
Denaturation
Annealing
Elongation/Extension
What happens to the number of DNA molecules after each cycle of PCR
It doubles, so after 20 cycles (a standard run) millions of DNA molecules are now available
What is Taqpolymerase, how does it differ and where does it come from
It is DNA polymerase that comes from a thermophilic bacterium “Thermus aquaticus”. It has a high optimum temperature of about 72 degrees celsius
How is a DNA profile created?
DNA is obtained (from blood, root of hair, semen, etc)
PCR is used to amplify and produce large quantities of required fragment
restriction endonucleases are used to cut the amplified DNA to fragments
Fragments are separated by gel electrophoresis
What is recombinant DNA?
What is a transgenic organism?
rDNA is DNA that hase been introduced from another organism
A transgenic organism is an organism that contains nucleotide sequences from different species
What are some uses of genetic modification?
In crops, to give them pesticide properties, or provide extra nutritional value, or give them resistance to disease
In livestock, resistance to disease or pest
In bacteria, produce medicine eg. insulin
