gene technology Flashcards
genetic engineering steps
-isolate DNA contain gene
-insert DNA into a vector
-transformation- transferring of the DNA
-identification- finding the DNA in the organism
-growth/ cloning of successful clone cells
reverse transcriptase
-it’s an enzyme that turns mRNA into DNA
-it comes from viruses
-mRNA has no introns, so no splicing needs to occur, so bacteria can replicate the DNA
-in cells there are a lot of mRNA
restriction endonuclease
-it’s an enzyme that cuts DNA at recognition sites
-they create complimentary sticky ends and blunt ends (blunt ends are not useful for genetic engineering)
gene machine
-it’s a computer that makes a desired sequence
-the computer checks for safety and standards
-once the sequence is made it’s sent to a lab where a small sequence of DNA is made (oligonucleotides)
-the sequence is joined together to make a sequence of DNA, sticky ends can bind the sections together
-gene machines are quicker as there is no need to isolate DNA/ mRNA
vector
-something that takes a piece of DNA and transports it to a host cell
promotor
-added to the end of a gene
-it’s where RNA polymerase binds and helps ‘switch a gene on’
terminator
-added to the end of a gene
-tells RNA polymerase to stop making mRNA
genetic engineering
-isolate DNA/mRNA from an organism using restriction endonuclease/ reverse transcriptase
-cut plasmid and isolated DNA with the same restriction endonuclease to get complimentary sticky ends
-add a promotor and terminator to the gene
-use DNA Ligase to join the desired gene to a plasmid, forming phosphodiester bonds
-include a marker gene, e.g. glow in the dark
-transform host cell using Ca2+ and a heat shock, so plasmid passes through the membrane
-allow bacteria to grow and replicate on a plate where marker gene is expressed
-bacteria that glow in the dark have wanted gene
cloning animals
-can genetically engineer early stage embryos, as the gene will be present in most cells, this allows all cells to make the protein
-insert a promotor into genes that are produced and easily extracted (e.g. milk)
-extracting proteins from other places may be harmful
-expressing proteins in all cells may be harmful
PCR
-DNA is heated to 90-95C to separate the strands
-DNA is cooled to 55C so that primers can bind to complimentary base pairs
-DNA is heated to 72C and DNA polymerase joins nucleotides together, forming phosphodiester bonds
-the cycle is repeated and DNA is copied at an exponential rate
‘ingredients’ for PCR
-template DNA- this is the DNA to make more of
-Taq/ DNA polymerase- forms phosphodiester bonds
-free nucleotides- binds to template by complimentary base pairing
-primer- starts reaction, short piece of single stranded DNA, DNA polymerase binds
gel electrophoresis
-DNA is cut at areas of tandem repeats using restriction endonuclease
-DNA fragments are placed in wells at the top of an agar gel
-an electric current is applied over it
-DNA is -VE charge, due to PO43-
DNA moves towards the +VE electrode, but at different rates
-small fragments of DNA move further through the gel
-a ladder/ marker can be used to determine the size of the DNA fragments
DNA finger printing
-extracted DNA is cut with a restriction endonuclease at sites of variable number tandem repeats/ mini-satellites
-DNA is separated by gel electrophoresis, shorter fragments run further on the gel
-use southern blotting to transfer DNA to a nylon membrane
-use an alkaline solution to make DNA single stranded
-add a single stranded probe tagged with radioactive/ fluorescent molecule
-visualise DNA using an X-ray or UV light
what genetic councillors can advise on
-probability/ genetic risk of developing a disease based on DNA tests
-order genetic testing
-explain inheritance of diseases
-options of managing a diagnosis
-pros/ cons of certain treatments
what genetic councillors can’t advise on
-if you’ll get a disease
-what treatment you should take
-how severe a disease will be
-if you should have children
