Genetic engineering (AQA GCSE Biology): Revision Notes
Genetic engineering
What is genetic engineering?
Genetic engineering is a way of changing an organism's DNA to give it new characteristics. Scientists take a gene from one organism and put it into another organism. This allows the new organism to produce something it couldn't make before.
Think of it like copying a recipe from one cookbook and putting it into another cookbook. The second cookbook can now make that dish too!
How genetic engineering works
The process follows these main steps:
- Choose the gene - Scientists find the gene that produces the characteristic they want
- Cut out the gene - Special enzymes are used to cut the gene from its original chromosome
- Transfer the gene - The gene is moved into a cell from a different organism
- Insert into chromosome - The gene is placed into the new organism's chromosome
- Make the product - The cell can now produce the new characteristic
Key point: Genes can be transferred between any organisms - bacteria, plants, animals, or humans.
GM crops
Genetically modified (GM) crops are plants that have been changed using genetic engineering.
Benefits of GM crops
GM crops are designed to be:
- Disease resistant - They don't get plant diseases as easily
- Pest resistant - Insects can't damage them as much
- Herbicide resistant - Farmers can spray weedkiller on fields without harming the crop
These improvements help farmers grow more food with bigger and better harvests.
Concerns about GM crops
Scientists worry about several potential issues:
- Wild plants - GM genes might spread to wild flowers and affect them
- Insects - There might be less food available for helpful insects
- Human health - More research is needed to check GM crops are completely safe to eat
Real examples
Insulin from bacteria
Worked Example: Engineering Bacteria to Produce Insulin
- People with diabetes need insulin injections
- Bacteria don't normally make human insulin
- Scientists put the human insulin gene into bacteria
- The bacteria now produce lots of insulin for medical use
Sheep producing human proteins
Worked Example: Engineering Sheep for Protein Production
- Some people have lung and liver problems because they can't make a certain protein
- Scientists put human genes into sheep
- The sheep now produce this human protein in their milk
- The protein can be collected from the milk to treat patients
Future research
Scientists are working on using genetic engineering to treat inherited disorders. They hope to fix faulty genes in people's cells. However, some people have ethical concerns about changing human genes.
Key Points to Remember:
- Genetic engineering moves genes between different organisms to create new characteristics
- The process uses enzymes to cut and insert genes into chromosomes
- GM crops help farmers but there are concerns about effects on wildlife and health
- Bacteria can be engineered to make human medicines like insulin
- Research continues into treating genetic disorders, but ethical issues need consideration