AQA GCSE Genetic engineering(Biology)

AQA GCSE Genetic engineering (Biology)

Genetic Engineering

Genetic engineering is the process of modifying the genome of an organism. This is done by inserting a gene from another organism. The aim is to give a desired characteristic.

How to carry out genetic engineering

Genetic Engineering in Medicine

Bacteria can be genetically engineered to produce useful substances.

An example is Human insulin which is used to treat diabetes

In the future it may help treat inherited disorders, by adding the correct working allele of a gene to a cell.

Using Genetic Engineering to produce human insulin

1. Cells from the pancreas contain the human insulin gene.

2. The gene from the pancreatic cells is cut out using an enzyme

3.A plasmid is extracted from a bacterium.

4. The same enzyme that is used to cut out the human insulin gene in stage 2 is used to cut open the plasmid.

5. The human insulin gene is inserted into the plasmid

6. An enzyme is used to seal the human insulin gene into the plasmid

7. Bacterium takes up the plasmid

8. Bacterium divides to produce more bacteria. All of these bacteria will contain a copy of the human insulin gene, so they will produce human insulin.

Benefits of Genetic Engineering

Agriculture

Plant crops have been genetically engineered to be resistant to diseases or to produce bigger better fruits.

Genetic engineering can increase crop yield by making plants resistant to insect attack. This means fewer crops are damaged, so more food is produced from the same area of land.

It can also make crops resistant to herbicides, allowing farmers to kill weeds without harming the crop. This reduces competition for light, water and minerals, leading to better growth and higher yields.

As a result, farmers may need to use fewer insecticides, which can reduce costs and environmental damage.

Medicine

Genetic engineering allows microorganisms such as bacteria to produce human proteins, for example insulin used to treat diabetes. This provides a large, reliable and pure supply, unlike older methods which used animal insulin.

It also has the potential to treat inherited genetic disorders by inserting a working version of a faulty gene into a patient’s cells (gene therapy).

Risks and Concerns of Genetic Engineering

Environmental risks

GM crops that are resistant to insects may lead to a decline in insect populations. This can disrupt food chains (e.g. fewer insects means fewer birds).

GM crops may cross-pollinate with wild plants, spreading modified genes. This could lead to reduced biodiversity or the growth of “superweeds” resistant to herbicides.

Health risks

GM crops may contain new proteins that could cause allergic reactions.

The long-term effects on human health are not yet fully known.

Concerns that antibiotic resistance genes used in modification could transfer to bacteria.

Ethical concerns

Some people believe genetic engineering is unnatural because genes are transferred between species.

Concerns about “playing God” or interfering with natural processes.

Worries about large companies controlling food production.

Some people think it is wrong to modify organisms for human benefit.

Evaluation of Genetic Engineering

Genetic engineering can provide major benefits, particularly in medicine and food production. For example, genetically engineered bacteria can produce human insulin, which is essential for treating diabetes, and GM crops can increase yields and reduce the need for chemical pesticides.

However, there are also significant risks. GM crops may reduce biodiversity by affecting insect populations and could spread modified genes to wild plants through cross-pollination. There are also concerns about unknown long-term effects on human health, such as allergies.

Overall, genetic engineering is useful and important, but it should be carefully regulated and tested to minimise risks. Whether it is acceptable depends on how the benefits are balanced against the potential environmental and health impacts.

Practice Questions

1.What is meant by genetic engineering?

2.Describe how a gene is transferred into bacteria using genetic engineering.

3.What useful substance is produced by genetically engineered bacteria to treat diabetes?