Genetic modification · Year 12
In Year 12 you get fluent with: gene therapy.
Genetic engineering changes an organism’s genome by adding a useful gene from another organism. Enzymes cut the gene out, a vector such as a bacterial plasmid carries it into the new cells, and the organism then makes the protein the gene codes for. Bacteria make human insulin this way, and GM crops can resist pests or make extra vitamins. People weigh these benefits against concerns about safety and the environment.
Key facts
- Genetic engineering changes an organism's genome by adding a gene from another organism. Bacteria have been given the human insulin gene, and crops have been given genes to resist insect pests or weedkillers or to make more vitamins.
- The steps: enzymes cut the gene out; it is inserted into a vector, such as a bacterial plasmid or a virus; the vector carries it into the target cells. In plants and animals the gene is put in at an early stage, so all the cells get it.
- Concerns about GM organisms include genes spreading to wild plants, effects on insects and wild flowers, unknown long-term effects on health, and whether it is right to change genes.
- Gene therapy aims to treat inherited disorders by putting a working allele into a patient's cells.
Worked examples
Example 1
What is genetic engineering?
Answer: changing the genome of an organism by putting in a gene from another organism
Example 2
Put the steps of genetic engineering in order.
Answer: enzymes cut the gene out → it is put into a vector such as a plasmid → the vector carries it into the cells → the organism makes the protein
Example 3
Describe how bacteria can be engineered to make human insulin.
Answer: enzymes cut out the insulin gene; it is put into a plasmid; the plasmid is taken up by bacteria, which then make insulin
Example 4
Which technique produced these: rice given genes so that it makes a substance the body turns into vitamin A?
Answer: genetic engineering
Example 5
Which of these is a benefit of genetic engineering?
Answer: crops with higher yields
Example 6
Which of these is a concern about GM crops?
Answer: genes from GM crops could spread to wild plants
Example 7
Give one advantage and one disadvantage of GM crops.
Answer: advantage: higher yields or resistance to pests; disadvantage: genes could spread to wild plants, and effects are not fully known