Genetic engineering Flashcards
Define genetic engineering:
Manipulation of the genome to achieve desired outcome.
How is it possible to insert a gene from a different species into human DNA?
DNA =universal
Almost all organisms = same 4 nitrogenous bases
Same codons code for same amino acids.
Transcription/translation =universal: means that the transferred DNA can be translated within cells of GMOs.
What does genetic engineering entail?
Isolating gene for a desirable characteristic in 1 organism + placing it into another organism –> use suitable vector.
What does palendromic refer t?
Can be read same backwards and forwards
DNA sequence need to known prior to make DNA probe.
What does the term transgenic refer to?
Carries a gene from another organism
Mostly known as GMO
What does the term recombinant refer to?
Altered DNA with introduced nucleotides.
How to isolate the desired gene?
DNA probe used to locate a gene within the genome
–> cut out using restriction endonuclease
= sticky ends: easier to insert gene into the DNA of another organism.
Amplify DNA (PCR)
What is another technique used to isolate desired gene?
Induce (switch on) expression of desired gene.
Extract mRNA
Use reverse transcriptase to form single stranded cDNA
Amplify cDNA
Cut the ends of cDNA with a restriction endonuclease
What are the advantages of the 2nd technique?
Easier to identify desired gene
Particular cell = specific types of mRNA.
e.g: Beta cells in pancreas (insulin) = produce lots of insulin mRNA molecules
What does synthetic biology refer to?
involvesthe transfer of fragments of DNAfromone organism/speciesinto anotherorganism/species
Describe plasmids as vectors:
Can replicate independently
Plasmid combines with host DNA = recombinant DNA.
Contains marker gene
Useful to determine if bacteria has been taken up by plasmid by growing bacteria in media containing antibiotic.
How is a DNA fragment inserted into a plasmid?
Cut plasmid using same restriction enzymes used to isolate DNA fragments
Leads to complementary sticky ends to the sticky ends of DNA fragments
Once complementary bases of two sticky ends lined up , DNA ligase forms phosphodiester bonds.
What does the 2nd marker gene show?
Show plasmid contains recombinant gene.
Restriction enzyme cuts within marker gene to insert desired gene
Successful = marker gene not function.
How is the vector transferred into the host cell?
Electroporation: small electrical current makes membrane porous so plasmid moves into cell.
Eukaryotic cells: DNA passes through cell membrane = nuclear membrane fuse with nuclear DNA.
Power of current heavily controlled so membrane not permanently damaged.
What is another method of transferring a vector?
Culture bacterial cells
+ plasmids in calcium-rich solutions
Increase temp
Causes bacterial membranes to become permeable. –> plasmids enter
How are plants genetically modified?
Agrobacterium used.
Desired gene e.g: pest production, herbicide-resistance placed in plasmid alomg with marker gene
Carried in plant cell DNA.
Transgenic plant cells from a callus
Why is it harder to engineer the DNA of eukaryotic animals?
Animal cell membranes less easy to manipulate than plant cell membranes.
