Genetic Engineering Flashcards
Recombinant DNA?
DNA made by artificially joining Pisces of DNA from different species
Transgenic organism?
Organism containing nucleotide sequences from different species
Genetically modified organism?
Organism with at has introduced genetic material
Genetic engineering?
Technique used to modify the characteristics of an organism
Steps that must be taken to genetically modify an organism?
Identification of the desired gene
Isolation of the gene
Multiplication of the gene
Identification of the cells with the new gene
How can genes be extracted?
Restriction endonuclease
mRNA and reverse transcriptase
What are restriction endonucleas?
Enzymes in bacteria used as a defense mechanism
How do restriction endonucleases extract genes?
They separate the DNA strand at the specific base sequence by cutting the sugar phosphate bond in an uneven way to give sticky ends or straight across to give blunt ends
Sticky ends:they can easily form bonds with the complementary bases
Blunt ends: nucleotides can be added to give sticky ends
mRNA and reverse transcriptase?
The mRNA transcribed for a gene is used to isolate it
When isolated, it’s combined with a reverse transcriptase enzyme+nucleotides to created 1 strand of complementary DNA
DNA polymerase will convert the strand into a double strand of DNA
Where do reverse transcriptase enzymes come from and what do they do?
Retroviruses
Catalyze the reaction that reverses transcription
Use of Vectors?
Used to transfer the desired gene to a foreign cell
Types of vectors?
Plasmids
Viruses
Lipososmes
What are plasmids and how are they used?
Circular rings of DNA
Endonuclease cuts the plasmids to give it sticky ends
DNA ligase forms phosphodiester between the DNA backbone and the plasmid to form a recombinant plasmid
Viruses as vectors?
Used in gene therapy to treat diseases
What are liposomes?
Liposomes as vectors?
Vesicles with a phospholipid bilayer
Used to carry non mutated genes into host cells
What are promoters?
Regions of DNA that determine witch genes are expressed because they are where DNA polymers bind to start transcription
How were promoters used to to produce b-galactosidase and insulin?
Scientists added the insulting gene with the b-galactosidase to share a promoter in a bacteria
The promoter switched on when the bacteria needed to metabolize lactose
The bacteria was grown in places contains lactose but no glucose and it produced insulin and b- galctosidse
What are marker genes?
Genes transferred with the desired gene to help identify which cells have been altered
Why did scientists stop using antibiotic genes as marker genes?
There’s a risk of the antibiotic genes getting transferred other bacteria including antibiotic resistant bacteria which would make the antibiotics less active
How can the antibiotic resistant genes spread?
Conjunction- the transfer of genetic material from one bacteria to another
Transduction- the transfer of genetic material through viruses
How are genes that express flouriscent proteins used as markers?
The desired gene and green fluorescent protein (GFP) are linked to a promoter
The premodern is activated and the protein is expressed
The recombinant bacteria are detected because they glow under UV light
Why are fluorescent genes used?
They’re easy to identify
More economical
No risk of antibiotic resistance
Stages of polymerase chain reaction (PCR)?
Denaturation: DNA is heated to 95C to break the hydrogen bonds
Annealing: temp is decreased to 50-60 so primers anneal to the ends of the strands
Elongation: temp is increased to 75 for min 1 minute because it’s the optimum temperature for tap polymerase to build the complementary strand
What is tac polymerase used?
Where does it come from?
Because it can work in high temperatures with high efficiency
Comes from thermophilic bacterium thermos aquaitius
