Equal numbers of lymphocytes from populations R and S were exposed to a sample containing molecule X. The number of activated lymphocytes was recorded.
| Condition | Activated lymphocytes |
|---|---|
| Population R, exposed to X | 86 |
| Population R, not exposed to X | 4 |
| Population S, exposed to X | 5 |
| Population S, not exposed to X | 3 |
Which conclusion is best supported by these results?
X is an antigen recognised equally by lymphocytes in both populations.
X is an antibody produced by lymphocytes in population R.
X is an antigen recognised by lymphocytes in population R.
X is a receptor on lymphocytes in population R.
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.