Applications in Medicine and Health: producing recombinant medicines such as insulin, making vaccines and monoclonal antibodies, diagnostics and genetic screening, and the promise of gene therapy and stem cells

What this module is about

Medicine is where biotechnology has changed the most lives, and this module brings the earlier techniques together to do real medical work. You see how recombinant DNA makes medicines, how the immune system is harnessed through vaccines and antibodies, how disease and faulty genes are detected, and how cells and genes themselves might be repaired. Each application reuses ideas from the genetic engineering and laboratory modules, so this is where the toolkit shows its purpose.

The full set of dot points for this module is at /sg-o-level/biotechnology/syllabus/applications-in-medicine-and-health.

Making medicines: recombinant insulin

The dot point on producing insulin and medicines is the classic worked example of recombinant DNA technology. The human insulin gene is cut out and inserted into a plasmid using a restriction enzyme and DNA ligase, the recombinant plasmid is put into bacteria, and the transformed bacteria are grown in a bioreactor where they read the gene and make human insulin, which is then extracted and purified. This is the whole earlier toolkit in one process, and it delivers a pure, plentiful supply without relying on animal pancreases.

Harnessing immunity: vaccines and monoclonal antibodies

The dot point on vaccines and monoclonal antibodies covers two different strategies. A vaccine contains a harmless form or part of a pathogen that trains the body's own immune system to make antibodies and memory cells, giving long-lasting protection before infection. A monoclonal antibody is a single type of antibody made in the laboratory that binds one specific target; it acts directly, for example in diagnosis or treatment, rather than training the immune system. The key contrast is train the body versus give a ready-made tool.

Finding disease: diagnostics and genetic screening

The dot point on diagnostics and genetic screening shows biotechnology detecting problems early. PCR amplifies and detects a pathogen's DNA, DNA probes and profiling identify specific sequences, and monoclonal antibodies power test kits. Genetic screening checks a person's DNA for disease-causing alleles, sometimes before symptoms appear. This power raises implications: who should know the result, and how might it be used, which links forward to the bioethics module.

Repairing cells and genes: gene therapy and stem cells

The dot point on gene therapy and stem cells covers the frontier. Gene therapy adds a working copy of a faulty gene, usually delivered by a vector into the patient's cells. Stem cells are unspecialised cells that can divide and develop into different cell types, offering a way to replace damaged tissue. Both are promising but limited: gene delivery is technically hard and can carry safety risks, treatments are costly, and some sources of stem cells raise ethical concerns. A good answer always pairs the potential with a limitation.

How the module fits together

• The toolkit applied. Recombinant insulin reuses restriction enzymes, ligase, transformation and bioreactors in one chain.
• Two immune strategies. Vaccines train the body; monoclonal antibodies are ready-made targeted tools.
• Detection then decision. Diagnostics and screening find disease and faulty genes, raising ethical questions.
• Potential with limits. Gene therapy and stem cells are promising but constrained by safety, cost and ethics.

Check your knowledge

A mix of recall and reasoning across the four dot points. Try them timed, then check the solutions.

1. List, in order, the main steps in producing human insulin using recombinant DNA technology. (3 marks)
2. State one difference between a vaccine and a monoclonal antibody. (2 marks)
3. Name one way biotechnology is used to diagnose disease. (1 mark)
4. Outline the principle of gene therapy. (2 marks)
5. State one potential and one limitation of using stem cells in medicine. (2 marks)