Open - Inverness Royal Academy

roachavocadoBiotechnologie

14 déc. 2012 (il y a 9 années et 1 mois)

381 vue(s)


define genetic engineering




the transfer of gene(s) from one organism to another




if genes are transferred between different species


a
genetically modified organism (GMO)

or
transgenic

organism
is produced


state the advantages of genetic engineering over
artificial selection




new varieties produced in one generation




element of chance removed




allows transfer of genes between species


describe two methods of locating genes on a
chromosome






banding patterns




when stained chromosomes show a unique pattern of light
and dark bands




by comparing the banding pattern on normal and mutated
chromosomes it is possible to identify the location of genes
responsible for a specific characteristic





gene probes




a gene probe is a
small piece of single
-
stranded DNA or
RNA

with a
base sequence complementary

to that of the gene
being sought




a radioactive or luminescent chemical (
marker
) is attached




the DNA containing the desired gene is
cut
-
up into small
fragments

using enzymes




it is then converted into
single
-
strand format

using
chemical or heat treatment




the gene probe is then added and it
attaches to the DNA
fragment containing the desired gene


state the name and function of the enzymes involved
in genetic engineering




endonuclease enzymes
are used to cut the DNA into
fragments










ligase enzymes are used to seal new gene(s) into the
genome of another organism

sequence the stages involved in
genetic engineering

(transfer of the
human insulin gene

to the
E. coli

bacterium
)




human DNA cut into fragments

by an endonuclease enzyme



plasmids (small rings of DNA) removed from
E. coli



all
contain gene for resistance to an antibiotic



plasmids cut open

using same endonuclease enzyme



human DNA fragments inserted into plasmids

using a
ligase enzyme



recombinant plasmids mixed with
E. coli

cells



only some
take
-
up a plasmid



E. coli

grown on agar containing antibiotic



those that
have not taken
-
up a plasmid killed



gene probe

added to identify
E. coli

colony that contains
plasmid with human insulin gene



E. coli

grown in a
fermenter



produce human insulin



insulin
purified

and made available to diabetics



name examples of GMOs and their products /
characteristics




E. Coli



produce
insulin
,
human growth hormone



sheep


factor VIII blood
-
clotting protein

produced in their
milk



crop plants


improved yields
,
enhanced disease
resistance
,
herbicide resistance
,
increased nutritional value
,
wider

environmental tolerance


discuss the potential positive and

negative impacts of genetic engineering