7.3 Flashcards
recombinant dna
DNA that has been formed artificially by combining DNA from different organisms
genetic engineering
1- isolating required gene - restriction enzyme
2-inserting gene into vector - ligase
3-transformation, gene is delivered into required cell
e.g microinjection
4-identifacation of host cells
5-grow cells with new gene on large scale - cloning
tranformation
vector needs to be placed back into the host cells
these cells are said to be transformed
- one way is to place the cells into ice cold calcium chloride to make cell walls permeable
-then you add to water bath at 42* for 2 mins
-then put back on ice
vectors
transfer required gene and gene markers into new cells
can recombine with appropriate host chromosome but others remain as autonomous recombinant plasmids
gene guns
dna is shot into cell at high speed carrier on minute gold or tungsten pellets.
some cells survive and accept DNA
liposome wrapping
the gene to be inserted is wrapped in liposomes (spheres formed from a lipid bilayer) these fuse with the cell membrane as can pass through it to deliver DNA into cytoplasm
microinjection
dna is injected into a cell through a fine micropippete.
this is manipulated using a micromanipulator
not very accurate method
many cells have to be injected before one is successful
but it is the method with most success
genetic engeneering
restriction enzymes make cuts in dna making sticky ends
also can cut plasmids open
section of target DNA added to host and sticky ends line up
ligase joins together
isolating genes method 1
reverse transcriptase
rna is taken from target cell
reverse transcriptase catalyses the production of DNA from RNa and nucelotides
DNA polymerase and free nulceotides from double stranded DNA
isolating genes method 2
restriction endonuclease
gene removed using restriction enzymes
different enzymes cut different positions
-recognition sequence
gene machine
computer examines amino acid sequences
creates small non overlapping section of DNA
joined to create desired gene
PCR is used to amplify
making gm plants
usualy use the bacterium agrobacterium tumerfaciens
which causes tumors in plants
contains a plasmid called Ti which transfers gm into plants
as plants remain totipotents tissue culture can then be used
knockout organisms
one or more genes silenced
-similar gene added so origional cannot be read
can be used to identify function of genes
gm crops benefits egs
flood resistant rice
pesticide resitance
changing nutrients
gm soya bean
herbecide resistance
fatty acid balance
