21.1 producing DNA fragments Flashcards
what are the 5 stages of making a protein using the DNA technology?
- isolation
- insertion
- transformation
- identification
- growth/ cloning
what is recombinant DNA?
DNA of 2 different organisms that have been combined
what are transgenic organisms?
organisms that have recombinant DNA
what are genetically modified organisms?
organisms that have recombinant DNA
what are the 3 methods of producing DNA fragments?
- mRNA -> cDNA using reverse transcriptase
- using restriction endonucleases to cut fragments
- creating the gene using a gene machine
where does reverse transcriptase come from?
retroviruses e.g. HIV
what does reverse transcriptase catalyse?
mRNA to cDNA
what is the method for using reverse transcriptase to get a DNA fragment?
- obtain mRNA from a cell that readily produces the protein
- add reverse transcriptase
- cDNA is made
- add DNA polymerase
- DNA made
what does restriction endonuclease do?
cuts DNA in straight or staggered ends
what are staggered ends also called?
sticky ends
why is a restriction endonuclease that recognises a 50 base pairs better than a restriction endonuclease that recognises 6?
- more specific
- as statistically appears less often
what are straight ends also called?
blunt ends
where does restriction endonuclease come from?
bacteria
what is the method that involves a gene machine?
- feed desired nucleotide sequence into the computer
- nucleotide added one at a time to form a oligonucleotide
- oligonucleotides overlap and are joined together to make a gene
- made double- stranded using PCR
- replicated DNA forms using PCR
- gene inserted into plasmid as has sticky ends
