Please enable JavaScript.
Coggle requires JavaScript to display documents.
Biotechnology and Genetic engineering, Part 3 MMP - Coggle Diagram
Biotechnology and Genetic engineering
, Part 3 MMP
Applications of genetic engineering:
Production of human insulin:
This hormone can be produced by genetically modified bacteria and has been in use since 1982. The
human insulin gene is inserted into bacteria, which then secrete human insulin.
The human insulin produced in this way is
purer
.
GM Crops:
Genetic engineering has
huge potential benefits in agriculture
but, apart from a relatively small range of crop plants, most developments are in the experimental or trial stages.
Pest resistance:
The bacterium, Bacillus thuringiensis,
produces a toxin that kills caterpillars and other insect larvae
. The toxin has been in use for some years as an
insecticide
.
The
gene for the toxin
has been successfully introduced into some plant species
using a bacterial vector.
The plants produce the toxin and
show increased resistance to attack by insect larvae.
The
gene
is also
passed on to the plant’s offspring.
Advantages and disadvantages of GM crops:
Process of genetic engineering:
There are present in the cytoplasm a
number of small, circular pieces of DNA called plasmids
. The plasmids often
carry genes
that give the bacterium resistance to particular antibiotics such as tetracycline and ampicillin.
Restriction enzymes
are produced by bacteria. T
hey ‘cut’ DNA molecules at specific sites.
By using a selected restriction enzyme, DNA molecules extracted from different organisms can be cut at predictable sites and made to produce lengths of DNA that contain specific genes.
DNA from human cells
can be extracted and restriction enzymes used to
‘cut’ out a sequence of DNA
that includes a gene, e.g. the gene for production of insulin.
These lengths have sticky ends.
Plasmids are extracted from bacteria and ‘cut open’ with the same restriction enzyme.
If the human DNA is then
added to a suspension of the plasmids, some of the human DNA will attach to some of the plasmids by their sticky ends
, and the plasmids will then close up again, given suitable enzymes such as
ligase
.
The DNA in these plasmids is called
recombinant DNA.
The bacteria can be
induced
to take up the plasmids.
Given suitable nutrient solutions,
bacteria multiply rapidly and produce vast numbers of offspring.
Each daughter bacterium will
contain the same DNA
and the
same plasmids as the parent
. The offspring form a clone and the
insulin gene is said to be cloned by this method.
The bacteria are cultured in special vessels called
fermenters
and the
insulin that they produce can be extracted
from the culture medium and
purified for use in treating diabetes.