Scientists developed a treatment containing a toxic drug attached to a monoclonal antibody for patients with one type of cancer.
Before treatment, cancer cells from each patient were tested for antigen K. The patients were placed into two groups. The table shows the mean results.
| Group | Cancer cells carrying antigen K (%) | Mean tumour volume before treatment (cm3\text{cm}^3cm3) | Mean tumour volume after treatment (cm3\text{cm}^3cm3) |
|---|---|---|---|
| 1 | 80 | 36 | 9 |
| 2 | 25 | 40 | 30 |
Calculate how many times as great the percentage decrease in mean tumour volume was in group 1 as in group 2.
Explain how the results provide evidence that the monoclonal antibody binds to antigen K.
Doctors also test a sample of each patient's healthy cells for antigen K. Explain why this information is needed before deciding whether to use the treatment.
87 exam-style questions on Edexcel GCSE Biology 5.3 Immune system and medicines, covering 5.3.1 The specific immune system, 5.3.2 Response to immunisation, 5.3.3 Advantages and disadvantages of immunisation, 5.3.4 Antibiotics and bacterial infections, 5.3.5 Aseptic techniques in culturing, 5.3.6 Cross-sectional areas of cultures, 5.3.7 Stages of developing new medicines, and 5.3.8 Production of monoclonal antibodies. Each one has a worked solution and a mark scheme showing where the marks go.