Genetic technology Flashcards
what is genetic engineering (3)
removal of gene from one organism
transfer to another
so it can be expressed
what are the tools for genetic engineering
restriction enzymes
vectors
what is the role of restriction enzymes in bacteria
role is to restrict viral infection in bacteria - they recognise + break DNA from virus
describe restriction enzymes
enzymes bind to specific target site on DNA and cuts
what ways can restriction enzymes cut
straight ends = blunt ends
staggered fashion = sticky ends
what is unique about sticky ends
can hydrogen bond complementary to other bases of other DNA cut with same enzyme
examples of vectors (3)
plasmids
viruses
liposomes
how are plasmids prepared as vectors
bacteria treated with enzymes to break cell wall and spun in centrifuge
plasmids of circular DNA cut using same restriction enzyme
what is recombinant DNA
DNA made by joining pieces of different sources
why is recombinant DNA used (7)
can produce large quantities; product exactly same as human protein; product has same amino acid sequence; no immune response; no side effect; no risk of transfer in disease; easier to obtain purified product;
describe plasmids
small/circular piece of double stranded DNA;
why are plasmids used in gene technology (7)
replicate independantly; high copy number; easy to extract from bacteria; can be cut using restriction enzyme; gene can be inserted; taken up by bacteria; acts as vector;
what are the ingredients for insulin production (4)
reverse transcriptase
DNA polymerase
restriction enzymes
DNA ligase
describe role of reverse transcriptase
make single strand of DNA from mRNA
describe role of DNA polymerase
link nucleotides by complementary base pairing to form double stranded DNA
describe role of restriction enzymes
cut plasmids at specific sites to create sticky ends
describe role of DNA ligase
seals sugar-phosphate backbone by adding a phosphate group
what are the three steps of insulin production
isolation of human gene
preparation of vector
formation of recombinant DNA
describe isolation of human gene (5)
mRNA from B cells in pancreas extracted;
mRNA with code for insulin isolated;
reverse transcriptase uses mRNA as template to make single strand DNA;
single strand DNA → double strand DNA by DNA polymerase;
restriction enzyme cuts sticky ends on DNA;
describe the preparation of vector (2)
plasmids extracted from bacteria;
same restriction enzymes cut to produce complementary sticky ends;
describe formation of recombinant DNA (6)
insulin DNA + plasmids + ligase enzyme;
sticky ends bases form hydrogen bonds and DNA ligase seals sugar phosphate backbone;
recombinant DNA inserted back into bacteria;
gene is cloned by growing the bacterium;
bacteria produces insulin and grown on large scale;
extraction and purification of insulin;