Download B3a Worksheet 3: DNA - School

B1b: 7
Genetic engineering – cut and paste!
Here is a description of how bacteria can be genetically engineered to produce human insulin.
Insulin is needed for the treatment of diabetics.
Many bacterial cells contain rings of DNA, which are called plasmids. These plasmids can be used
in genetic engineering.
Scientists have been able to identify which human gene controls the production of insulin. This gene
is ‘cut out’ from human DNA by special ‘chemical scissors’ called a restriction enzyme. This same
enzyme can cut open a plasmid. The human insulin gene is then inserted into the plasmid. Another
enzyme, called a ligase, joins the two ends of the insulin gene to the cut ends of the plasmid.
The plasmid has been recombined with the insulin gene. It is now called a recombinant plasmid, or
recombinant DNA. The recombinant plasmid now has to be put back into the bacterial cell. This
can be done by, literally, shocking the bacterium with a small, short electric shock. This makes
very small, temporary, holes in the bacterium’s cell wall. The recombinant plasmids quickly pass
through these holes before they close up again.
Bacteria that contain recombinant DNA will start to produce lots of insulin, but only if they are given
the right conditions.
First task
Draw a flow chart that shows the stages of making a bacterium that contains recombinant DNA.
Is genetic engineering ethical?
In recent years lots of different plants and animals have been genetically engineered.
This has made them more useful to us.
Here is a table of some of these plants and animals.
How have they been made more useful?
Examples
Make chemicals that stop insects eating them
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Make them resistant to herbicides
Make them resistant to virus infections
Used in the production of medicines
Make them grow more quickly
Some varieties of apples
Cotton plants
Maize
Tomatoes
Cabbage
Oilseed rape
Peanuts
Potatoes
Cucumbers
Melons
Papaya
Tobacco
Cattle
Goats
Mice
Sheep
Carp (a type of fish)
Cattle
Pigs
Salmon
B1b: 7
Evolution and environment – continued
Second task
Explain how each reason listed in the table is directly useful to us.
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B1b: 7
Answers to Worksheets
Worksheet B1b: 7
First task:
Second task:
Pupils to consider each reason why genetically engineered organisms are useful to us
and then explain it:
Make chemical which stop insects eating them:
 Greater productivity
Make them resistant to herbicides:
 fields can be sprayed to kill weeds with no danger of harming crop plants
Resistant to viral infections:
 Greater productivity
Used in the production of medicines:
 Could be seen as more natural rather than producing medicines in a lab
They grow more quickly:
 faster productivity and hence bigger profits
B1b: 7
Technician’s Notes
Starter activity
Resources:
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newspaper cutting describing the destruction of a GM crop by protestors