Genetic engineering (AQA GCSE Biology Combined Science): Revision Notes
Genetic engineering
What is genetic engineering?
Genetic engineering is a way of changing an organism's genome (all its genes) to give it new characteristics. Scientists do this by taking a gene from one organism and putting it into another organism.
This process lets us create organisms with useful traits they wouldn't normally have, opening up possibilities that don't exist in nature.
The process
Genetic engineering is a precise scientific method that allows scientists to transfer specific traits between organisms. Here's how it works:
Worked Example: The Genetic Engineering Process
Step 1: Scientists find the gene they want from any organism (bacteria, humans, plants, or animals)
Step 2: They cut out this gene from a chromosome using special enzymes
Step 3: The gene gets transferred to a cell from a different organism
Step 4: The gene is inserted into a chromosome in the new cell
Step 5: The new organism can now produce the characteristic from the transferred gene
This means genes can move between completely different types of organisms - like putting a human gene into bacteria. This cross-species transfer is what makes genetic engineering so powerful and unique.
GM crops
Genetically modified (GM) crops are plants that have been genetically engineered to have useful characteristics.
Benefits of GM crops
GM crops offer significant advantages for modern agriculture. They can be made to be:
- Resistant to plant diseases - so fewer crops die from illness
- Resistant to insect pests - insects can't damage them as easily
- Resistant to herbicides - farmers can spray weedkiller without harming the crop plants
These improvements help farmers produce bigger yields with better quality fruits and vegetables.
Concerns about GM crops
While GM crops offer benefits, there are legitimate scientific concerns that need consideration:
Potential Environmental Impacts:
- GM crops might affect wild flower populations if herbicides kill too many weeds
- Insect populations might be harmed if there's less food available for them
- We need more research into whether GM crops are completely safe for humans to eat
Examples of genetic engineering
Bacteria making human insulin
People with diabetes need insulin injections. This is how scientists have revolutionised insulin production:
Worked Example: Engineering Bacteria for Insulin Production
Step 1: The human insulin gene gets cut out from human chromosomes
Step 2: This gene gets inserted into bacteria using genetic engineering techniques
Step 3: The bacteria now make human insulin as they grow and reproduce
Step 4: Large amounts of bacteria can produce lots of insulin for patients who need it
Engineering sheep
Scientists have created sheep that produce human proteins in their milk, offering hope for treating genetic disorders:
Worked Example: Sheep Producing Human Proteins
The Problem: Some people have genetic disorders that stop them making important proteins
The Solution:
- Scientists put human genes into sheep
- The sheep's milk now contains these human proteins
- The milk can be used to treat patients with genetic disorders
Research and ethical concerns
Scientists continue researching genetic engineering to help people with inherited disorders. They hope genetic engineering could overcome symptoms of genetic diseases and improve quality of life for patients.
Ethical Considerations
However, some people have ethical concerns about genetic engineering. They worry about:
- Whether it's right to change organisms genetically
- Potential long-term effects we don't understand yet
- Whether genetic engineering is being used responsibly
The scientific community continues to debate these ethical questions while conducting research under strict safety guidelines and regulations.
Key Points to Remember:
- Genetic engineering transfers genes between different organisms to create new characteristics
- The process involves cutting, transferring, and inserting genes using special enzymes
- GM crops can resist diseases, pests, and herbicides to increase food production
- Bacteria can be engineered to make human medicines like insulin
- There are both benefits and concerns about genetic engineering that scientists continue to research